Comparison operations in memory

ABSTRACT

Examples of the present disclosure provide apparatuses and methods related to performing comparison operations in a memory. An example apparatus might include a first group of memory cells coupled to a first access line and configured to store a first element. An example apparatus might also include a second group of memory cells coupled to a second access line and configured to store a second element. An example apparatus might also include sensing circuitry configured to compare the first element with the second element by performing a number of AND operations, OR operations, SHIFT operations, and INVERT operations without transferring data via an input/output (I/O) line.

PRIORITY INFORMATION

This application is a Non-Provisional of U.S. Provisional ApplicationNo. 62/008,004, filed Jun. 5, 2014, the contents of which areincorporated herein by reference.

TECHNICAL FIELD

The present disclosure relates generally to semiconductor memoryapparatuses and methods, and more particularly, to apparatuses andmethods related to performing comparison operations in a memory.

BACKGROUND

Memory devices are typically provided as internal, semiconductor,integrated circuits in computers or other electronic systems. There aremany different types of memory including volatile and non-volatilememory. Volatile memory can require power to maintain its data (e.g.,host data, error data, etc.) and includes random access memory (RAM),dynamic random access memory (DRAM), static random access memory (SRAM),synchronous dynamic random access memory (SDRAM), and thyristor randomaccess memory (TRAM), among others. Non-volatile memory can providepersistent data by retaining stored data when not powered and caninclude NAND flash memory, NOR flash memory, and resistance variablememory such as phase change random access memory (PCRAM), resistiverandom access memory (RRAM), and magnetoresistive random access memory(MRAM), such as spin torque transfer random access memory (STT RAM),among others.

Electronic systems often include a number of processing resources (e.g.,one or more processors), which may retrieve and execute instructions andstore the results of the executed instructions to a suitable location. Aprocessor can comprise a number of functional units (e.g., hereinreferred to as functional unit circuitry (FUC)) such as arithmetic logicunit (ALU) circuitry, floating point unit (FPU) circuitry, and/or acombinatorial logic block, for example, which can execute instructionsto perform logical operations such as AND, OR, NOT, NAND, NOR, and XORlogical operations on data (e.g., one or more operands).

A number of components in an electronic system may be involved inproviding instructions to the functional unit circuitry for execution.The instructions may be generated, for instance, by a processingresource such as a controller and/or host processor. Data (e.g., theoperands on which the instructions will be executed to perform thelogical operations) may be stored in a memory array that is accessibleby the FUC. The instructions and/or data may be retrieved from thememory array and sequenced and/or buffered before the FUC begins toexecute instructions on the data. Furthermore, as different types ofoperations may be executed in one or multiple clock cycles through theFUC, intermediate results of the operations and/or data may also besequenced and/or buffered.

In many instances, the processing resources (e.g., processor and/orassociated FUC) may be external to the memory array, and data can beaccessed (e.g., via a bus between the processing resources and thememory array) to execute instructions. Data can be moved from the memoryarray to registers external to the memory array via a bus.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram of an apparatus in the form of a computingsystem including a memory device in accordance with a number ofembodiments of the present disclosure.

FIG. 2A illustrates a schematic diagram of a portion of a memory arrayin accordance with a number of embodiments of the present disclosure.

FIG. 2B illustrates a schematic diagram of a portion of a memory arrayin accordance with a number of embodiments of the present disclosure.

FIG. 3 illustrates a schematic diagram of a portion of a memory array inaccordance with a number of embodiments of the present disclosure.

FIG. 4A illustrates a table showing the states of memory cells of anarray at a particular phase associated with performing a comparisonoperation in accordance with a number of embodiments of the presentdisclosure.

FIG. 4B illustrates a table showing the states of memory cells of anarray at a particular phase associated with performing a comparisonoperation in accordance with a number of embodiments of the presentdisclosure.

FIG. 4C illustrates a table showing the states of memory cells of anarray at a particular phase associated with performing a comparisonoperation in accordance with a number of embodiments of the presentdisclosure.

FIG. 5 illustrates a timing diagram associated with performing a numberof logical operations using sensing circuitry in accordance with anumber of embodiments of the present disclosure.

FIG. 6 illustrates a timing diagram associated with performing a numberof logical operations using sensing circuitry in accordance with anumber of embodiments of the present disclosure.

FIG. 7 illustrates a timing diagram associated with performing a numberof logical operations using sensing circuitry in accordance with anumber of embodiments of the present disclosure.

FIG. 8 illustrates a timing diagram associated with performing a numberof logical operations using sensing circuitry in accordance with anumber of embodiments of the present disclosure.

FIG. 9 illustrate a timing diagram associated with performing a numberof logical operations using sensing circuitry in accordance with anumber of embodiments of the present disclosure.

FIG. 10 illustrates a timing diagram associated with performing a numberof logical operations using sensing circuitry in accordance with anumber of embodiments of the present disclosure.

FIG. 11 is a schematic diagram illustrating sensing circuitry havingselectable logical operation selection logic in accordance with a numberof embodiments of the present disclosure.

FIG. 12 is a logic table illustrating selectable logic operation resultsimplemented by a sensing circuitry in accordance with a number ofembodiments of the present disclosure.

DETAILED DESCRIPTION

The present disclosure includes apparatuses and methods related toperforming comparison operations in a memory. As used herein, acomparison operation includes comparing vectors. A comparison operationcan be performed on a first element (e.g., first vector) and a secondelement (e.g., second vector). An element can be stored in a groupmemory cells coupled to an access line. For example, a first group ofmemory cells coupled to a first access line can be configured to store afirst element. A second group of memory cells coupled to a second accessline can be configured to store a second element. The comparisonoperation can compare the first element with the second element byperforming a number of AND operations, OR operations, SHIFT operations,and INVERT operations without transferring data via an input/output(I/O) line.

As used herein, a first element and a second element can be numericalvalues that are compared to (e.g., against) each other. That is, a firstvalue can be compared to a second value and/or the second value can becompared to the first value. A comparison operation can be used todetermine whether the first value is greater than the second value,whether the second value is greater than the first value, and/or whetherthe first value is equal to the second value.

In a number of examples, an element can represent an object and/or otherconstruct, which may be represented by a bit-vector. As an example, acomparison operation can be performed to compare objects by comparingthe bit-vectors that represent the respective objects.

A number of embodiments of the present disclosure can provide areduction of the number of computations and/or time involved inperforming a number of comparison operations (e.g., compare functions)relative to previous approaches. For instance, the number ofcomputations and/or the time can be reduced due to an ability to performvarious portions of the number of comparison operations in parallel inthroughput (e.g., simultaneously). Performing a number of comparisonoperations as described herein can also reduce power consumption ascompared to previous approaches. In accordance with a number ofembodiments, a comparison operation can be performed on elements (e.g.,data in the form of bit-vectors stored in an array) without transferringdata out of the memory array and/or sensing circuitry via a bus (e.g.,data bus, address bus, control bus, etc.), which can reduce the timeand/or power needed to transfer data to a host in order to perform thecomparison operation. Also, the result from the comparison operation canbe formatted as a two bit-vectors. The two bit-vectors can incorporategreater than and less than results. The two bit-vectors can be providedto other single instruction multiple data (SIMD) operations (e.g.,bit-vector division) and/or advanced pattern search applications in theform of masks. A comparison operation can involve performing a number oflogical operations (e.g., AND operations, OR operations, SHIFToperations, INVERT operations, and BLOCKOR operations etc.). However,embodiments are not limited to these examples. As used herein SIMDoperations is defined as performing a same operation on multipleelements in parallel (e.g., simultaneously).

In various previous approaches, elements (e.g., a first data value and asecond data value) to be compared may be transferred from the array andsensing circuitry to a number of registers via a bus comprisinginput/output (I/O) lines. The number of registers can be used by aprocessing resource such as a processor, microprocessor, and/or computeengine, which may comprise ALU circuitry and/or other functional unitcircuitry configured to perform the appropriate logical operations.However, often only a single comparison function can be performed by theALU circuitry, and transferring data to/from memory from/to registersvia a bus can involve significant power consumption and timerequirements. Even if the processing resource is located on a same chipas the memory array, significant power can be consumed in moving dataout of the array to the compute circuitry (e.g., ALU), which can involveperforming a sense line address access (e.g., firing of a column decodesignal) in order to transfer data from sense lines onto I/O lines,moving the data to the array periphery, and providing the data to aregister in association with performing a comparison operation, forinstance.

In the following detailed description of the present disclosure,reference is made to the accompanying drawings that form a part hereof,and in which is shown by way of illustration how one or more embodimentsof the disclosure may be practiced. These embodiments are described insufficient detail to enable those of ordinary skill in the art topractice the embodiments of this disclosure, and it is to be understoodthat other embodiments may be utilized and that process, electrical,and/or structural changes may be made without departing from the scopeof the present disclosure. As used herein, the designators “F,” “M,”“N,” “P,” “R,” “S,” “U,” “V,” “X,” and “W,” particularly with respect toreference numerals in the drawings, indicates that a number of theparticular feature so designated can be included. As used herein, “anumber of” a particular thing can refer to one or more of such things(e.g., a number of memory arrays can refer to one or more memoryarrays).

The figures herein follow a numbering convention in which the firstdigit or digits correspond to the drawing figure number and theremaining digits identify an element or component in the drawing.Similar elements or components between different figures may beidentified by the use of similar digits. For example, 130 may referenceelement “30” in FIG. 1, and a similar element may be referenced as 230in FIG. 2. As will be appreciated, elements shown in the variousembodiments herein can be added, exchanged, and/or eliminated so as toprovide a number of additional embodiments of the present disclosure. Inaddition, as will be appreciated, the proportion and the relative scaleof the elements provided in the figures are intended to illustratecertain embodiments of the present invention, and should not be taken ina limiting sense.

FIG. 1 is a block diagram of an apparatus in the form of a computingsystem 100 including a memory device 160 in accordance with a number ofembodiments of the present disclosure. As used herein, a memory device160, a memory array 130, and/or sensing circuitry 150 might also beseparately considered an “apparatus.”

System 100 includes a host 110 coupled to memory device 160, whichincludes a memory array 130. Host 110 can be a host system such as apersonal laptop computer, a desktop computer, a digital camera, a mobiletelephone, or a memory card reader, among various other types of hosts.Host 110 can include a system motherboard and/or backplane and caninclude a number of processing resources (e.g., one or more processors,microprocessors, or some other type of controlling circuitry). Thesystem 100 can include separate integrated circuits or both the host 110and the memory device 160 can be on the same integrated circuit. Thesystem 100 can be, for instance, a server system and/or a highperformance computing (HPC) system and/or a portion thereof. Althoughthe example shown in FIG. 1 illustrates a system having a Von Neumannarchitecture, embodiments of the present disclosure can be implementedin non-Von Neumann architectures (e.g., a Turing machine), which may notinclude one or more components (e.g., CPU, ALU, etc.) often associatedwith a Von Neumann architecture.

For clarity, the system 100 has been simplified to focus on featureswith particular relevance to the present disclosure. The memory array130 can be a DRAM array, SRAM array, STT RAM array, PCRAM array, TRAMarray, RRAM array, NAND flash array, and/or NOR flash array, forinstance. The array 130 can comprise memory cells arranged in rowscoupled by access lines (which may be referred to herein as word linesor select lines) and columns coupled by sense lines (which may bereferred to herein as digit lines or data lines). Although a singlearray 130 is shown in FIG. 1, embodiments are not so limited. Forinstance, memory device 160 may include a number of arrays 130 (e.g., anumber of banks of DRAM cells). An example DRAM array is described inassociation with FIG. 2.

The memory device 160 includes address circuitry 142 to latch addresssignals provided over an I/O bus 156 (e.g., a data bus) through I/Ocircuitry 144. Address signals are received and decoded by a row decoder146 and a column decoder 152 to access the memory array 130. Data can beread from memory array 130 by sensing voltage and/or current changes onthe sense lines using sensing circuitry 150. The sensing circuitry 150can read and latch a page (e.g., row) of data from the memory array 130.The I/O circuitry 144 can be used for bi-directional data communicationwith host 110 over the I/O bus 156. The write circuitry 148 is used towrite data to the memory array 130.

Control circuitry 140 decodes signals provided by control bus 154 fromthe host 110. These signals can include chip enable signals, writeenable signals, and address latch signals that are used to controloperations performed on the memory array 130, including data read, datawrite, and data erase operations. In various embodiments, the controlcircuitry 140 is responsible for executing instructions from the host110. The control circuitry 140 can be a state machine, a sequencer, orsome other type of controller.

An example of the sensing circuitry 150 is described further below inassociation with FIG. 2. For instance, in a number of embodiments, thesensing circuitry 150 can comprise a number of sense amplifiers and anumber of compute components, which may comprise an accumulator and canbe used to perform logical operations (e.g., on data associated withcomplementary sense lines). In a number of embodiments, the sensingcircuitry (e.g., 150) can be used to perform comparison operations usingdata stored in array 130 as inputs and store the results of thecomparison operations back to the array 130 without transferring via asense line address access (e.g., without firing a column decode signal).As such, a comparison function can be performed using sensing circuitry150 rather than and/or in addition to being performed by processingresources external to the sensing circuitry 150 (e.g., by a processorassociated with host 110 and/or other processing circuitry, such as ALUcircuitry, located on device 160 (e.g., on control circuitry 140 orelsewhere)).

In various previous approaches, data associated with a comparisonoperation, for instance, would be read from memory via sensing circuitryand provided to an external ALU. The external ALU circuitry wouldperform the comparison functions using the elements (which may bereferred to as operands or inputs) and the result could be transferredback to the array via the local I/O lines. In contrast, in a number ofembodiments of the present disclosure, sensing circuitry (e.g., 150) isconfigured to perform a comparison operation on data stored in memorycells in memory array 130 and store the result back to the array 130without enabling a local I/O line coupled to the sensing circuitry.

As such, in a number of embodiments, registers and/or an ALU external toarray 130 and sensing circuitry 150 may not be needed to perform thecomparison function as the sensing circuitry 150 can perform theappropriate computations involved in performing the comparison functionusing the address space of memory array 130. Additionally, thecomparison function can be performed without the use of an externalprocessing resource.

FIG. 2A illustrates a schematic diagram of a portion of a memory array230 including sensing circuitry 250 in accordance with a number ofembodiments of the present disclosure. In FIG. 2A, a memory cellcomprises a storage element (e.g., capacitor) and an access device(e.g., transistor). For instance, transistor 202-1 and capacitor 203-1comprises a memory cell, and transistor 202-2 and capacitor 203-2comprises a memory cell, etc. In this example, the memory array 230 is aDRAM array of 1T1C (one transistor one capacitor) memory cells. In anumber of embodiments, the memory cells may be destructive read memorycells (e.g., reading the data stored in the cell destroys the data suchthat the data originally stored in the cell is refreshed after beingread). The cells of the memory array 230 are arranged in rows coupled byword lines 204-X (Row X), 204-Y (Row Y), etc., and columns coupled bypairs of complementary data lines DIGIT(n−1)/DIGIT(n−1)_,DIGIT(n)/DIGIT(n)_, DIGIT(n+1)/DIGIT(n+1)_. The individual data linescorresponding to each pair of complementary data lines can also bereferred to as data lines 205-1 (D) and 205-2 (D_) respectively.Although only three pair of complementary data lines are shown in FIG.2A, embodiments of the present disclosure are not so limited, and anarray of memory cells can include additional columns of memory cellsand/or data lines (e.g., 4,096, 8,192, 16,384, etc.).

Memory cells can be coupled to different data lines and/or word lines.For example, a first source/drain region of a transistor 202-1 can becoupled to data line 205-1 (D), a second source/drain region oftransistor 202-1 can be coupled to capacitor 203-1, and a gate of atransistor 202-1 can be coupled to word line 204-X. A first source/drainregion of a transistor 202-2 can be coupled to data line 205-2 (D_), asecond source/drain region of transistor 202-2 can be coupled tocapacitor 203-2, and a gate of a transistor 202-2 can be coupled to wordline 204-Y. The cell plate, as shown in FIG. 2A, can be coupled to eachof capacitors 203-1 and 203-2. The cell plate can be a common node towhich a reference voltage (e.g., ground) can be applied in variousmemory array configurations.

The memory array 230 is coupled to sensing circuitry 250 in accordancewith a number of embodiments of the present disclosure. In this example,the sensing circuitry 250 comprises a sense amplifier 206 and a computecomponent 231 corresponding to respective columns of memory cells (e.g.,coupled to respective pairs of complementary data lines). The senseamplifier 206 can comprise a cross coupled latch, which can be referredto herein as a primary latch. The sense amplifier 206 can be configured,for example, as described with respect to FIG. 2B.

In the example illustrated in FIG. 2A, the circuitry corresponding tocompute component 231 comprises a static latch 264 and an additional tentransistors that implement, among other things, a dynamic latch. Thedynamic latch and/or static latch of the compute component 231 can becollectively referred to herein as a secondary latch, which can serve asan accumulator. As such, the compute component 231 can operate as and/orbe referred to herein as an accumulator. The compute component 231 canbe coupled to each of the data lines D 205-1 and D_ 205-2 as shown inFIG. 2A. However, embodiments are not limited to this example. Thetransistors of compute component 231 can all be n-channel transistors(e.g., NMOS transistors), for example.

In this example, data line D 205-1 can be coupled to a firstsource/drain region of transistors 216-1 and 239-1, as well as to afirst source/drain region of load/pass transistor 218-1. Data line D_205-2 can be coupled to a first source/drain region of transistors 216-2and 239-2, as well as to a first source/drain region of load/passtransistor 218-2.

The gates of load/pass transistor 218-1 and 218-2 can be commonlycoupled to a LOAD control signal, or respectively coupled to aPASSD/PASSDB control signal, as discussed further below. A secondsource/drain region of load/pass transistor 218-1 can be directlycoupled to the gates of transistors 216-1 and 239-2. A secondsource/drain region of load/pass transistor 218-2 can be directlycoupled to the gates of transistors 216-2 and 239-1.

A second source/drain region of transistor 216-1 can be directly coupledto a first source/drain region of pull-down transistor 214-1. A secondsource/drain region of transistor 239-1 can be directly coupled to afirst source/drain region of pull-down transistor 207-1. A secondsource/drain region of transistor 216-2 can be directly coupled to afirst source/drain region of pull-down transistor 214-2. A secondsource/drain region of transistor 239-2 can be directly coupled to afirst source/drain region of pull-down transistor 207-2. A secondsource/drain region of each of pull-down transistors 207-1, 207-2,214-1, and 214-2 can be commonly coupled together to a reference voltageline 291-1 (e.g., ground (GND)). A gate of pull-down transistor 207-1can be coupled to an AND control signal line, a gate of pull-downtransistor 214-1 can be coupled to an ANDinv control signal line 213-1,a gate of pull-down transistor 214-2 can be coupled to an ORinv controlsignal line 213-2, and a gate of pull-down transistor 207-2 can becoupled to an OR control signal line.

The gate of transistor 239-1 can be referred to as node S1, and the gateof transistor 239-2 can be referred to as node S2. The circuit shown inFIG. 2A stores accumulator data dynamically on nodes S1 and S2.Activating the LOAD control signal causes load/pass transistors 218-1and 218-2 to conduct, and thereby load complementary data onto nodes S1and S2. The LOAD control signal can be elevated to a voltage greaterthan V_(DD) to pass a full V_(DD) level to S1/S2. However, elevating theLOAD control signal to a voltage greater than V_(DD) is optional, andfunctionality of the circuit shown in FIG. 2A is not contingent on theLOAD control signal being elevated to a voltage greater than V_(DD).

The configuration of compute component 231 shown in FIG. 2A has thebenefit of balancing the sense amplifier for functionality when thepull-down transistors 207-1, 207-2, 214-1, and 214-2 are conductingbefore the sense amplifier 206 is fired (e.g., during pre-seeding of thesense amplifier 206). As used herein, firing the sense amplifier 206refers to enabling the sense amplifier 206 to set the primary latch andsubsequently disabling the sense amplifier 206 to retain the set primarylatch. Performing logical operations after equilibration is disabled (inthe sense amp), but before the sense amplifier fires, can save powerusage because the latch of the sense amplifier does not have to be“flipped” using full rail voltages (e.g., V_(DD), GND).

Inverting transistors can pull-down a respective data line in performingcertain logical operations. For example, transistor 216-1 (having a gatecoupled to S2 of the dynamic latch) in series with transistor 214-1(having a gate coupled to an ANDinv control signal line 213-1) can beoperated to pull-down data line 205-1 (D), and transistor 216-2 (havinga gate coupled to S1 of the dynamic latch) in series with transistor214-2 (having a gate coupled to an ANDinv control signal line 213-2) canbe operated to pull-down data line 205-2 (D_).

The latch 264 can be controllably enabled by coupling to an activenegative control signal line 212-1 (ACCUMB) and an active positivecontrol signal line 212-2 (ACCUM) rather than be configured to becontinuously enabled by coupling to ground and V_(DD). In variousembodiments, load/pass transistors 208-1 and 208-2 can each having agate coupled to one of a LOAD control signal or a PASSD/PASSDB controlsignal.

According to some embodiments, the gates of load/pass transistors 218-1and 218-2 can be commonly coupled to a LOAD control signal. In theconfiguration where the gates of load/pass transistors 218-1 and 218-2are commonly coupled to the LOAD control signal, transistors 218-1 and218-2 can be load transistors. Activating the LOAD control signal causesthe load transistors to conduct, and thereby load complementary dataonto nodes S1 and S2. The LOAD control signal can be elevated to avoltage greater than V_(DD) to pass a full V_(DD) level to S1/S2.However, the LOAD control signal need not be elevated to a voltagegreater than V_(DD) is optional, and functionality of the circuit shownin FIG. 2A is not contingent on the LOAD control signal being elevatedto a voltage greater than V_(DD).

According to some embodiments, the gate of load/pass transistor 218-1can be coupled to a PASSD control signal, and the gate of load/passtransistor 218-2 can be coupled to a PASSDb control signal. In theconfiguration where the gates of transistors 218-1 and 218-2 arerespectively coupled to one of the PASSD and PASSDb control signals,transistors 218-1 and 218-2 can be pass transistors. Pass transistorscan be operated differently (e.g., at different times and/or underdifferent voltage/current conditions) than load transistors. As such,the configuration of pass transistors can be different than theconfiguration of load transistors.

Load transistors are constructed to handle loading associated withcoupling data lines to the local dynamic nodes S1 and S2, for example.Pass transistors are constructed to handle heavier loading associatedwith coupling data lines to an adjacent accumulator (e.g., through theshift circuitry 223, as shown in FIG. 2A). According to someembodiments, load/pass transistors 218-1 and 218-2 can be configured toaccommodate the heavier loading corresponding to a pass transistor butbe coupled and operated as a load transistor. Load/pass transistors218-1 and 218-2 configured as pass transistors can also be utilized asload transistors. However, load/pass transistors 218-1 and 218-2configured as load transistors may not be capable of being utilized aspass transistors.

In a number of embodiments, the compute component 231, including thelatch 264, can comprise a number of transistors formed on pitch with thetransistors of the corresponding memory cells of an array (e.g., array230 shown in FIG. 2A) to which they are coupled, which may conform to aparticular feature size (e.g., 4F², 6F², etc.). According to variousembodiments, latch 264 includes four transistors 208-1, 208-2, 209-1,and 209-2 coupled to a pair of complementary data lines D 205-1 and D_205-2 through load/pass transistors 218-1 and 218-2. However,embodiments are not limited to this configuration. The latch 264 can bea cross coupled latch (e.g., gates of a pair of transistors, such asn-channel transistors (e.g., NMOS transistors) 209-1 and 209-2 are crosscoupled with the gates of another pair of transistors, such as p-channeltransistors (e.g., PMOS transistors) 208-1 and 208-2). As describedfurther herein, the cross coupled latch 264 can be referred to as astatic latch.

The voltages or currents on the respective data lines D and D_ can beprovided to the respective latch inputs 217-1 and 217-2 of the crosscoupled latch 264 (e.g., the input of the secondary latch). In thisexample, the latch input 217-1 is coupled to a first source/drain regionof transistors 208-1 and 209-1 as well as to the gates of transistors208-2 and 209-2. Similarly, the latch input 217-2 can be coupled to afirst source/drain region of transistors 208-2 and 209-2 as well as tothe gates of transistors 208-1 and 209-1.

In this example, a second source/drain region of transistor 209-1 and209-2 is commonly coupled to a negative control signal line 212-1 (e.g.,ground (GND) or ACCUMB control signal similar to control signal RnIFshown in FIG. 2B with respect to the primary latch). A secondsource/drain region of transistors 208-1 and 208-2 is commonly coupledto a positive control signal line 212-2 (e.g., V_(DD) or ACCUM controlsignal similar to control signal ACT shown in FIG. 2B with respect tothe primary latch). The positive control signal 212-2 can provide asupply voltage (e.g., V_(DD)) and the negative control signal 212-1 canbe a reference voltage (e.g., ground) to enable the cross coupled latch264. According to some embodiments, the second source/drain region oftransistors 208-1 and 208-2 are commonly coupled directly to the supplyvoltage (e.g., V_(DD)), and the second source/drain region of transistor209-1 and 209-2 are commonly coupled directly to the reference voltage(e.g., ground) so as to continuously enable latch 264.

The enabled cross coupled latch 264 operates to amplify a differentialvoltage between latch input 217-1 (e.g., first common node) and latchinput 217-2 (e.g., second common node) such that latch input 217-1 isdriven to either the activated positive control signal voltage (e.g.,V_(DD)) or the activated negative control signal voltage (e.g., ground),and latch input 217-2 is driven to the other of the activated positivecontrol signal voltage (e.g., V_(DD)) or the activated negative controlsignal voltage (e.g., ground).

FIG. 2B illustrates a schematic diagram of a portion of a memory arrayin accordance with a number of embodiments of the present disclosure.According to various embodiments, sense amplifier 206 can comprise across coupled latch. However, embodiments of the sense amplifier 206 arenot limited to the a cross coupled latch. As an example, the senseamplifier 206 can be current-mode sense amplifier and/or single-endedsense amplifier (e.g., sense amplifier coupled to one data line). Also,embodiments of the present disclosure are not limited to a folded dataline architecture.

In a number of embodiments, a sense amplifier (e.g., 206) can comprise anumber of transistors formed on pitch with the transistors of thecorresponding compute component 231 and/or the memory cells of an array(e.g., 230 shown in FIG. 2A) to which they are coupled, which mayconform to a particular feature size (e.g., 4F², 6F², etc.). The senseamplifier 206 comprises a latch 215 including four transistors coupledto a pair of complementary data lines D 205-1 and D_ 205-2. The latch215 can be a cross coupled latch (e.g., gates of a pair of transistors,such as n-channel transistors (e.g., NMOS transistors) 227-1 and 227-2are cross coupled with the gates of another pair of transistors, such asp-channel transistors (e.g., PMOS transistors) 229-1 and 229-2). Asdescribed further herein, the latch 215 comprising transistors 227-1,227-2, 229-1, and 229-2 can be referred to as a primary latch. However,embodiments are not limited to this example.

The voltages or currents on the respective data lines D and D_ can beprovided to the respective latch inputs 233-1 and 233-2 of the crosscoupled latch 215 (e.g., the input of the secondary latch). In thisexample, the latch input 233-1 is coupled to a first source/drain regionof transistors 227-1 and 229-1 as well as to the gates of transistors227-2 and 229-2. Similarly, the latch input 233-2 can be coupled to afirst source/drain region of transistors 227-2 and 229-2 as well as tothe gates of transistors 227-1 and 229-1. The compute component 233(e.g., accumulator) can be coupled to latch inputs 233-1 and 233-2 ofthe cross coupled latch 215 as shown; however, embodiments are notlimited to the example shown in FIG. 2B.

In this example, a second source/drain region of transistor 227-1 and227-2 is commonly coupled to an active negative control signal 228(RnIF). A second source/drain region of transistors 229-1 and 229-2 iscommonly coupled to an active positive control signal 265 (ACT). The ACTsignal 265 can be a supply voltage (e.g., V_(DD)) and the RnIF signalcan be a reference voltage (e.g., ground). Activating signals 228 and265 enables the cross coupled latch 215.

The enabled cross coupled latch 215 operates to amplify a differentialvoltage between latch input 233-1 (e.g., first common node) and latchinput 233-2 (e.g., second common node) such that latch input 233-1 isdriven to one of the ACT signal voltage and the RnIF signal voltage(e.g., to one of V_(DD) and ground), and latch input 233-2 is driven tothe other of the ACT signal voltage and the RnIF signal voltage.

The sense amplifier 206 can also include circuitry configured toequilibrate the data lines D and D_ (e.g., in association with preparingthe sense amplifier for a sensing operation). In this example, theequilibration circuitry comprises a transistor 224 having a firstsource/drain region coupled to a first source/drain region of transistor225-1 and data line D 205-1. A second source/drain region of transistor224 can be coupled to a first source/drain region of transistor 225-2and data line D_ 205-2. A gate of transistor 224 can be coupled to gatesof transistors 225-1 and 225-2.

The second source drain regions of transistors 225-1 and 225-2 arecoupled to an equilibration voltage 238 (e.g., V_(DD)/2), which can beequal to V_(DD)/2, where V_(DD) is a supply voltage associated with thearray. The gates of transistors 224, 225-1, and 225-2 can be coupled tocontrol signal 225 (EQ). As such, activating EQ enables the transistors224, 225-1, and 225-2, which effectively shorts data line D to data lineD_ such that the data lines D and D_ are equilibrated to equilibrationvoltage V_(DD)/2. According to various embodiments of the presentdisclosure, a number of logical operations can be performed using thesense amplifier, and storing the result in the compute component (e.g.,accumulator).

As shown in FIG. 2A, the sense amplifier 206 and the compute component231 can be coupled to the array 230 via shift circuitry 223. In thisexample, the shift circuitry 223 comprises a pair of isolation devices(e.g., isolation transistors 221-1 and 221-2) coupled to data lines205-1 (D) and 205-2 (D_), respectively). The isolation transistors 221-1and 221-2 are coupled to a control signal 222 (NORM) that, whenactivated, enables (e.g., turns on) the isolation transistors 221-1 and221-2 to couple the corresponding sense amplifier 206 and computecomponent 231 to a corresponding column of memory cells (e.g., to acorresponding pair of complementary data lines 205-1 (D) and 205-2(D_)). According to various embodiments, conduction of isolationtransistors 221-1 and 221-2 can be referred to as a “normal”configuration of the shift circuitry 223.

In the example illustrated in FIG. 2A, the shift circuitry 223 includesanother (e.g., a second) pair of isolation devices (e.g., isolationtransistors 221-3 and 221-4) coupled to a complementary control signal219 (SHIFT), which can be activated, for example, when NORM isdeactivated. The isolation transistors 221-3 and 221-4 can be operated(e.g., via control signal 219) such that a particular sense amplifier206 and compute component 231 are coupled to a different pair ofcomplementary data lines (e.g., a pair of complementary data linesdifferent than the pair of complementary data lines to which isolationtransistors 221-1 and 221-2 couple the particular sense amplifier 206and compute component 231), or can couple a particular sense amplifier206 and compute component 231 to another memory array (and isolate theparticular sense amplifier 206 and compute component 231 from a firstmemory array). According to various embodiments, the shift circuitry 223can be arranged as a portion of (e.g., within) the sense amplifier 206,for instance.

Although the shift circuitry 223 shown in FIG. 2A includes isolationtransistors 221-1 and 221-2 used to couple particular sensing circuitry250 (e.g., a particular sense amplifier 206 and corresponding computecomponent 231) to a particular pair of complementary data lines 205-1(D) and 205-2 (D_) (e.g., DIGIT(n) and DIGIT(n)_) and isolationtransistors 221-3 and 221-4 are arranged to couple the particularsensing circuitry 250 to an adjacent pair of complementary data lines inone particular direction (e.g., adjacent data lines DIGIT(n+1) andDIGIT(n+1)_ shown to the right in FIG. 2A), embodiments of the presentdisclosure are not so limited. For instance, shift circuitry can includeisolation transistors 221-1 and 221-2 used to couple particular sensingcircuitry to a particular pair of complementary data lines (e.g.,DIGIT(n) and DIGIT(n)_ and isolation transistors 221-3 and 221-4arranged so as to be used to couple the particular sensing circuitry toan adjacent pair of complementary data lines in another particulardirection (e.g., adjacent data lines DIGIT(n−1) and DIGIT(n−1)_ shown tothe left in FIG. 2A).

Embodiments of the present disclosure are not limited to theconfiguration of shift circuitry 223 shown in FIG. 2A. In a number ofembodiments, shift circuitry 223 such as that shown in FIG. 2A can beoperated (e.g., in conjunction with sense amplifiers 206 and computecomponents 231) in association with performing compute functions such asadding and subtracting functions without transferring data out of thesensing circuitry 250 via an I/O line (e.g., local I/O line (IO/IO_)),for instance.

Although not shown in FIG. 2A, each column of memory cells can becoupled to a column decode line that can be activated to transfer, vialocal I/O line, a data value from a corresponding sense amplifier 206and/or compute component 231 to a control component external to thearray such as an external processing resource (e.g., host processorand/or other functional unit circuitry). The column decode line can becoupled to a column decoder (e.g., column decoder). However, asdescribed herein, in a number of embodiments, data need not betransferred via such I/O lines to perform logical operations inaccordance with embodiments of the present disclosure. In a number ofembodiments, shift circuitry 223 can be operated in conjunction withsense amplifiers 206 and compute components 231 to perform computefunctions such as adding and subtracting functions without transferringdata to a control component external to the array, for instance.

The sensing circuitry 250 can be operated in several modes to performlogical operations, including a first mode in which a result of thelogical operation is initially stored in the sense amplifier 206, and asecond mode in which a result of the logical operation is initiallystored in the compute component 231. Operation of the sensing circuitry250 in the first mode is described below with respect to FIGS. 3 and 4,and operation of the sensing circuitry 250 in the second mode isdescribed below with respect to FIGS. 7-10. Additionally with respect tothe first operating mode, sensing circuitry 250 can be operated in bothpre-sensing (e.g., sense amps fired before logical operation controlsignal active) and post-sensing (e.g., sense amps fired after logicaloperation control signal active) modes with a result of a logicaloperation being initially stored in the sense amplifier 206.

As described further below, the sense amplifier 206 can, in conjunctionwith the compute component 231, be operated to perform various logicaloperations using data from an array as input. In a number ofembodiments, the result of a logical operation can be stored back to thearray without transferring the data via a data line address access(e.g., without firing a column decode signal such that data istransferred to circuitry external from the array and sensing circuitryvia local I/O lines). As such, a number of embodiments of the presentdisclosure can enable performing logical operations and computefunctions associated therewith using less power than various previousapproaches. Additionally, since a number of embodiments eliminate theneed to transfer data across I/O lines in order to perform computefunctions (e.g., between memory and discrete processor), a number ofembodiments can enable an increased parallel processing capability ascompared to previous approaches.

FIG. 3 illustrates a schematic diagram of a portion of a memory array330 in accordance with a number of embodiments of the presentdisclosure. The array 330 includes memory cells 303-0, 303-1, 303-3,303-4, 303-5, 303-6, 303-7, 303-8, . . . , 303-J (e.g., referred togenerally as memory cells 303), coupled to rows of access lines 304-0,304-1, 304-2, 304-3, 304-4, 304-5, 304-6, . . . , 304-R and columns ofsense lines 305-0, 305-1, 305-2, 305-3, 305-4, 305-5, 305-6, 305-7, . .. , 305-S. Memory array 330 is not limited to a particular number ofaccess lines and/or sense lines, and use of the terms “rows” and“columns” does not intend a particular physical structure and/ororientation of the access lines and/or sense lines. Although notpictured, each column of memory cells can be associated with acorresponding pair of complementary sense lines (e.g., complementarysense lines 205-1 and 205-2 in FIG. 2A).

Each column of memory cells can be coupled to sensing circuitry (e.g.,sensing circuitry 150 shown in FIG. 1). In this example, the sensingcircuitry comprises a number of sense amplifiers 306-0, 306-1, 306-2,306-3, 306-4, 306-5, 306-6, 306-7, . . . , 306-U (e.g., referred togenerally as sense amplifiers 306) coupled to the respective sense lines305-0, 305-1, 305-2, 305-3, 305-4, 305-5, 305-6, 305-7, . . . , 305-S.The sense amplifiers 306 are coupled to input/output (I/O) line 334(e.g., a local I/O line) via access devices (e.g., transistors) 308-0,308-2, 308-3, 308-4, 308-5, 308-6, 308-7, . . . , 308-V. In thisexample, the sensing circuitry also comprises a number of computecomponents 331-0, 331-2, 331-3, 331-4, 331-5, 331-6, 331-7, . . . ,331-X (e.g., referred to generally as compute components 331) coupled tothe respective sense lines. Column decode lines 310-0 to 310-W arecoupled to the gates of transistors 308-0 to 308-V, respectively, andcan be selectively activated to transfer data sensed by respective senseamplifiers 306-0 to 306-U and/or stored in respective compute components331-0 to 331-X to a secondary sense amplifier 312. In a number ofembodiments, the compute components 331 can be formed on pitch with thememory cells of their corresponding columns and/or with thecorresponding sense amplifiers 306.

The sensing circuitry (e.g., compute components 331 and sense amplifiers306) is configured to perform a comparison operation in accordance witha number of embodiments described herein. The example given in FIGS. 4A,4B, and 4C demonstrates how a comparison operation can be performedusing data stored in array 330 as the inputs. The example involves usingthe elements (e.g., bits having logic “1” or logic “0”) stored in thememory cells coupled to access lines 304-0 to 304-R and commonly coupledto sense lines 305-0 to 305-S as the respective inputs to the comparisonoperation. The result of the comparison operation can be stored in array330 and/or can be transferred external to the array 330 (e.g., tofunctional unit circuitry of a host).

FIGS. 4A, 4B, and 4C illustrate a table showing the states of memorycells of an array at a number of particular phases associated withperforming a comparison operation in accordance with a number ofembodiments of the present disclosure. Column 496 of the table providesreference numbers (e.g., 1-8) for the rows of the table, and thereference numbers shown in the table correspond to the respectivereference numbers of the pseudocode described below. The bit-vectorvalues for each of the bit-vectors 476 (Row_Mask), 478 (Row_LowAct), 480(Row_Retained), 482 (Row_Object), 488 (srca), 490 (srcb), 492 (dest),and 494 (dest+1) are stored in the array at various comparison operationphases corresponding to reference numbers 1-6.

The bit-vectors 476, 478, 480, and 482 can be stored in respectivegroups of memory cells coupled to particular access lines, which may bereferred to as temporary storage rows 470 (e.g., rows that store datathat may be updated during various phases of a comparison operation).The bit-vectors 488, 490, 492, and 494 can be referred to as vectorarguments 472. FIGS. 4A-4C also indicate the bit-vector values for abit-vector 431 (Comp_Comp) stored in compute components (e.g., 331 shownin FIG. 3) of the array.

The scalar integer variables 484 (destc) and 486 (destpc) can be storedin memory (e.g., registers) associated with control circuitry 140 inFIG. 1. In a number of examples, destc 484 and/or destpc 486 can also bestored in in the array 130 in FIG. 1.

In FIGS. 4A, 4B, and 4C the values of the bit-vectors corresponding tothe rows 470 and/or the vector arguments 472 are shown in hexadecimalformat although the corresponding bit-vectors operated on during thecomparison operation can be stored as binary bit patterns in the array.For example, a srca bit-vector 488 (e.g., [0000 0011, 0000 1001, 00000010, 0000 1100] can be represented as [03, 09, 02, 0c] in hexadecimalformat. The values shown in FIGS. 4A, 4B, and 4C are shown inhexadecimal format for ease of reference.

In the examples used herein, bit-vector values may include commas and/orspaces for ease of reference. For instance, a bit-vector represented inhexadecimal notation as [03, 09, 02, 0c] can correspond to four 8-bitwide vector elements, with the four elements separated by a respectivecomma and space. However, the same bit-vector can be represented as [0309 02 0c] (e.g., without commas) and/or as [0309020c] (e.g., withoutcommas and without spaces).

In FIGS. 4A, 4B, and 4C changes to the sensing circuitry that stores thebit-vectors corresponding to Comp_Comp 431, the memory cells that storethe bit-vectors corresponding to the temporary storage rows 470 (e.g.,Row_Mask 476, Row_LowAct 478, Row_Retained 480, and Row_Object 482), andthe memory cells that store the bit-vectors corresponding to vectorarguments 472 (e.g., srca 488, srcb 490, dest 492, and dest+1 494) areindicated in bold font. For example, at reference 1, srca 488, srcb 490,dest 492, and dest+1 494 are shown in bold font indicating values of therespective bit-vectors have changed during an operation phase to whichthe reference number corresponds. Changes to destc 484 and destpc 486are also shown in bold font indicating changes to the memory in thecontrol circuitry 140.

In the example shown in FIGS. 4A, 4B, and 4C, each of srca 488 (e.g.,[0309020c]) and srcb 490 (e.g., [0705080c]) comprise four elements andare associated with four separate comparison operations.

For example, elements in a first element pair (e.g., 03 and 07 from srca488 and srcb 490, respectively) are compared in a first comparisonoperation. Elements in a second element pair (e.g., 09 and 05 from srca488 and srcb 490, respectively) are compared in a second comparisonoperation. Elements in a third element pair (e.g., 02 and 08 from srca488 and srcb 490, respectively) are compared in a third comparisonoperation, and elements in a fourth element pair (e.g., 0c and 0c fromsrca 488 and srcb 490, respectively) are compared in a fourth comparisonoperation.

A first group of memory cells that store srca 488 can be cells coupledto a particular access line (e.g., 304-0 in FIG. 3) and to a number ofsense lines (e.g., 305-0 to 305-31 in FIG. 3). The second group ofmemory cells that store srcb 490 can be cells coupled to a differentparticular access line (e.g., 304-1 in FIG. 3) and to a number of senselines (e.g., 305-0 to 305-31 in FIG. 3).

The four elements of srca 488 can be stored in the first group of memorycells. For example, a first element (e.g., 03) of srca 488 can be storedin memory cells that are coupled to access line 304-0 and sense lines305-0 to 305-7 in FIG. 3, a second element (e.g., 09) can be stored inmemory cells that are coupled to access line 304-0 and sense lines 305-8to 305-15 in FIG. 3, a third element (e.g., 02) can be stored in memorycells that are coupled to access line 304-0 and sense lines 305-16 to305-23 in FIG. 3, and a fourth element (e.g., 0c) can be stored inmemory cells that are coupled to access line 304-0 and sense lines305-34 to 305-31 in FIG. 3.

The four elements of srcb 490 can be stored in the second group ofmemory cells. For example, a first element (e.g., 07) of srcb 490 can bestored in memory cells that are coupled to access line 304-1 and senselines 305-0 to 305-7, a second element (e.g., 05) can be stored inmemory cells that are coupled to access line 304-1 and sense lines 305-8to 305-15, a third element (e.g., 08) can be stored in memory cells thatare coupled to access line 304-1 and sense lines 305-16 to 305-23, and afourth element (e.g., 0c) can be stored in memory cells that are coupledto access line 304-1 and sense lines 305-34 to 305-31.

Row_Mask 476, Row_LowAct 478, Row_Retained 480, and Row_Object 482include bit-vectors that are stored in a plurality of groups of memorycells. For instance, Row_Mask 476, Row_LowAct 478, Row_Retained 480, andRow_Object 482 can be stored in memory cells that are coupled torespective access lines 304-2 to 304-5 and to sense lines 305-0 to305-31. Destc 484 and destpc 486 include scalar integers that are usedin the comparison operation.

In this example, the first element in scra 488 has a decimal value of 3,which can be represented by bit-vector [0000 0011] with 8-bit width. Theparticular bits of the bit-vector can be stored in the cells coupled toaccess line 304-0 and to the corresponding respective sense lines 305-0to 305-7 (e.g., the most significant bit (MSB) of the bit-vector can bestored in the ROW 0 cell coupled to sense line 305-0, the next leastsignificant bit (LSB) can be stored in the ROW 0 cell coupled to senseline 305-1, . . . , and the LSB can be stored in the ROW 0 cell coupledto sense line 305-7) in FIG. 3. Similarly, the first element in srcb 490has a decimal value of 7, which can be represented by bit-vector [00000111], and the particular bits of the bit-vector can be stored in thecells coupled to access line 304-1 and to the corresponding respectivesense lines 305-0 to 305-7. As such, the respective bits of the 8-bitwide bit-vectors representing the first element in srca 488 and thefirst element in srcb 490 can be stored in cells coupled to respectivesame sense lines (e.g., columns). That is, in this example, the MSBs ofthe bit-vectors are stored in cells coupled to sense line 305-0, thenext least significant bits of the bit-vectors are stored in cellscoupled to sense line, 305-1, etc. For simplicity, Endian Byte order isignored. Rather, the bits in the logical word size are always incontiguous sequence with a least significant bit on the right to a mostsignificant bit on the left.

However, embodiments are not limited to this example. For instance,elements to be compared in accordance with embodiments described hereincan be represented by bit-vectors having a width other than 8-bits.Also, a plurality of elements can be represented by a particularbit-vector. For instance, a first 64-bit wide bit-vector could representfour elements each represented by a 16-bit wide bit-vector and could bestored in cells coupled to access line 304-0 (and to sense lines 305-0to 305-63), and a second 64-bit wide bit-vector could represent fourelements each represented by a 16-bit wide bit vector and could bestored in cells coupled to access line 304-1 (and to sense lines 305-0to 305-63). The four elements represented by the first 64-bit widebit-vector can be compared to the respective four elements representedby the second 64-bit wide bit-vector in accordance with embodimentsdescribed herein.

In a number of embodiments, the result of a comparison operation can bestored in a third group of memory cells, which can be cells coupled to anumber of particular access lines (e.g., 304-0 to 304-R in FIG. 3). Thethird group of memory cells can be used to store a first bit-vectorand/or a second bit-vector that indicates the result of the comparisonoperation. That is, the bit-vector(s) stored in the third group ofmemory cells can indicate whether the first element in srca 488 isgreater than the first element in srcb 490, whether the first element insrcb 490 is greater than the first element in srca 488, and/or whetherthe first element in srca 488 is equal to the first element srcb 490.The third group of memory cells can, for example, be cells coupled to anaccess line 304-7 or cells coupled to at least one of access line 304-0and access line 304-1. That is, the third group of memory cells can be asame group of memory cells as the first group of memory cells or thesecond group of memory cells. For instance, in the 8-bit wide bit-vectorexample above, the third group of memory cells can be cells coupled toaccess line 304-0 and to sense lines 305-0 to 305-7 and/or cells coupledto access line 304-1 and to sense lines 305-0 to 305-7.

The third group of memory cells can also comprise a first number ofmemory cells coupled to a particular access line and a second number ofmemory cells coupled to a different particular access line. The firstand second numbers of memory cells can store two different bit-vectorsthat together indicate the results of the comparison operation (e.g., ina 2-bit horizontal vector row). For example, a first result bit-vectorcan be stored in the first number of memory cells and a second resultbit-vector can be stored in the second number of memory cells.Particular bit patterns of the first and second result bit-vectors canindicate whether the first element in srca 488 is greater than the firstelement in srcb 490, whether the first element in srcb 490 is greaterthan the first element in srca 488, and/or whether the first element insrca 488 is equal to the first element in srcb 490.

For instance, as described further below, responsive to the firstelement in srca 488 being greater than the first element in srcb 490,the first result bit-vector can be a first bit pattern (e.g., [11111111]) and the second result bit-vector can be a second bit pattern(e.g., [0000 0000]), and responsive to the first element in srcb 490being greater than the first element in srca 488, the first resultbit-vector can be the second bit pattern (e.g., [0000 0000]) and thesecond result bit-vector can be the first bit pattern (e.g., [11111111]). Responsive to the first element in srcb 488 and the firstelement in srca 490 being equal, the first result bit-vector and thesecond result bit-vector can be the same bit pattern (e.g., [0000 0000]or [1111 1111]).

As an example, the first result bit-vector can be stored in the cellscoupled to access line 304-2 and to sense lines 305-0 to 305-7 shown inFIG. 3. The second result bit-vector can be stored in the cells coupledto access line 304-3 and to the sense lines 305-0 to 305-7, forinstance. In a number of examples, the first result bit-vector and/orthe second result bit-vector can be stored in cells coupled to an accessline to which cells storing the first and/or second elements beingcompared are coupled. For instance, if a first element is stored in afirst group of cells coupled to access line 304-0 and a second elementis stored in a second group of cells coupled to access line 304-1, athird group of cells storing the first and the second result bit-vectorsmay comprise cells coupled to access lines 304-0 and 304-1 in FIG. 3,respectively.

It is noted that a determination of whether a first element is greaterthan a second element may include a determination that the first elementis not less than the second element, but may not identify whether thefirst element is equal to the second element. That is, if the firstelement is not greater than the second element, then the second elementmay be greater than the first element or the first element may be equalto the second element.

Accordingly, a comparison operation can also include a determination ofwhether the second element is greater than the first element, which mayinclude a determination that the second element is not less than thefirst element. However, a determination that the second element is notless than the first element may not identify whether the second elementis equal to the first element. In a number of examples, performing acomparison operation on a first element and a second element can includeperforming a number of AND operations, OR operations, SHIFT operations,and INVERT operations without transferring data via an input/output(I/O) line. The number of AND operations, OR operations, INVERToperations, and SHIFT operations can be performed using sensingcircuitry on pitch with memory cells corresponding to respective columnsof complementary sense lines.

The below pseudocode represents instructions executable to perform anumber of comparison operations in a memory in accordance with a numberof embodiments of the present disclosure. The example pseudocode isreferenced using reference numbers 1-8, which correspond to therespective reference numbers 1-8 shown in column 496 of the table shownin FIGS. 4A, 4B, and 4C. For example, reference number one (1)corresponds to “Load srca, srcb” in the pseudocode, and reference numberthree (3) corresponds to “Obtain all Temp Rows” in the pseudocode.

-   1. Load srca, srcb.-   2. Determine element count in sub array for the vector length.-   3. Obtain all Temp Rows.-   4. Find MSB and store in Comp_Comp, Row_Mask, Row_Retained.-   5. Find MSB by shifting right with fixed vector for each length in    Comp_Comp.-   6. Right Shift for fixed length and store in Row_Object.-   7. For each Vector element:    -   7.a. Create Full Row_Mask for the element with bits enabled.    -   7.b Right Shift Row_Retained to the fixed length of the element.    -   7.c. Load srca in Comp_Comp    -   7.d. Do Comp_Comp AND operation with srcb    -   7.e. Store Inverse of Comp_Comp in Row_LowAct    -   7.f. Load Row_LowAct in Comp_Comp    -   7.g. Do Comp_Comp AND operation with srca    -   7.h. Do Comp_Comp AND operation with Row_Mask    -   7.i. Do Comp_Comp OR operation with dest    -   7.j. Store Com_Comp in dest    -   7.k. Load Row_LowAct in Comp_Comp    -   7.l. Do Comp_Comp AND operation with srcb    -   7.m. Do Comp_Comp AND operation with Row_Mask    -   7.n. Do Comp_Comp OR operation with dest+1    -   7.o. Store Comp_Comp in dest+1    -   7.p. Load dest in Comp_Comp    -   7.q. Do Comp_Comp AND operation with Row_Mask    -   7.r. Store Comp_Comp in Row_LowAct    -   7.s. For Vector fixed width:        -   7.s.i. Do Comp_Comp AND operation with Row_Mask        -   7.s.ii. Store Comp_Comp in Row_LowAct        -   7.s.iii. Do Comp_Comp AND operation with Row_Object        -   7.s.iv. Store return value of BLOCKOR operation into scalar            integer destc        -   7.s.v. Load Row_LowAct in Comp_Comp        -   7.s.vi. Shift Right    -   7.t. Load dest+1 in Comp_Comp    -   7.u. Do Comp_Comp AND operation with Row_Mask    -   7.v. Store Comp_Comp in Row_LowAct    -   7.w. For Vector fixed width:        -   7.w.i. Do Comp_Comp AND operation with Row_Mask        -   7.w.ii. Store Comp_Comp in Row_LowAct        -   7.w.iii. Do Comp_Comp AND operation with Row_Object        -   7.w.iv. Store result value of BLOCKOR operation into scalar            integer destpc        -   7.w.v. Load Row_LowAct in Comp_Comp        -   7.w.vi. Shift Right    -   7.x. If destc>destpc        -   7.x.i. Populate dest with Row_Mask        -   7.x.ii. Populate dest+1 with Inverse Row_Mask    -   7.y. else If destpc>destc        -   7.y.i. Populate dest+1 with Row_Mask        -   7.y.ii. Populate dest with Inverse Row_Mask    -   7.z. else        -   7.z.i. Populate dest and dest+1 with Inverse Row_Mask-   8. Free all Temp Rows and return.

For purposes of discussion, the above pseudocode will be divided into asetup phase and a comparison phase. The pseudocode referenced byreference numbers 1-6 can correspond to the setup phase. In a number ofembodiments, the setup phase can be performed simultaneously for all ofthe comparison operations. FIG. 4A illustrates the values of a number ofbit-vectors associated with performing a comparison operation after thesetup phase.

The pseudocode referenced by reference number 7 (e.g., 7.a -7.z.i) cancorrespond to the comparison phase. The comparison phase can further bedivided into a determination phase and a results phase. Thedetermination phase can correspond to the pseudocode reference byreference numbers 7.a. to 7.w.vi. The determination phase can beexecuted to determine whether the first element is greater than thesecond element in each of the element pairs, whether the second elementis greater than the first element in each of the element pairs, and/orwhether the first element is equal to the second element in each of theelement pairs. The values of a number of bit-vectors during execution ofan example comparison phase are shown in FIGS. 4B and 4C.

The pseudocode corresponding to the results phase can be executed tostore the results of the comparison operation. The results phase cancomprise the pseudocode referenced by reference numbers 7.x. to 7.z.i.In a number of examples, the results of the comparison operation can bestored in an array (e.g., array 330 in FIG. 3) without transferring datavia an I/O line (e.g., I/O line 334). In a number of examples, theresults of the comparison operation can be transferred to a locationother than array 330 in FIG. 3.

The comparison phase can include performing a number of iterations ofoperations. For example, the pseudocode corresponding to referencenumber 7 (e.g., “For each Vector element:”) can represent a “For” loopassociated with iterating through a number of logical operations foreach vector element pair of a number of vector element pairs beingcompared.

A first iteration of a “For” loop corresponding to reference number 7can be performed to compare a first element to a second element of afirst element pair, while subsequent iterations of the “For” loop can beperformed to compare additional element pairs. In a number of examples,each iteration of the “For” loop corresponding to reference number 7 canbe performed sequentially. Performing each iteration of the “For” loopsequentially can include concluding each iteration of the “For” loopbefore the next iteration of the “For” loop begins.

The pseudocode corresponding to reference number 1 (e.g., “Load srca,srcb”) is associated with storing srca 488 and srcb 490 into the array330 in FIG. 3. As described above, srca 488 and srcb 490 can eachinclude a number of elements to be compared. At reference number 1, thebit-vector [0309020c] is stored in a group of memory cells that storesrca 488, the bit-vector [0705080c] is stored in a group of memory cellsthat store srcb 490, the bit-vector [00000000] is stored in a pluralityof groups of memory cells that store dest 492 and dest+1 494. Atreference number 1, scalar integer 0 is stored in a register that storesdestc 484 and destpc 486.

The pseudocode corresponding to reference number 2 (e.g., “Determineelement count in sub array for the vector length”), is associated withdetermining the element count of srca 488 and srcb 490. Determining thecount of elements in srca 488 and srcb 490 can include determining thenumber of element pairs to be compared. At reference number 2, a vectorlength is also determined. Although not shown in FIG. 4A, the elementcount and the vector length can be stored in the rows 470 that storetemporary data. In FIGS. 4A, 4B, and 4C, the element count is four andthe vector length is eight. The vector length is eight (8) because eightbits are used to represent each element in an element bit-vector. Forexample, the 03 element in hexadecimal is represented by the [0000 0011]bit-vector with eight bits.

As an example, the element count can be determined based on the width ofsrca 488 and srcb 490 and on the element width (e.g., the number of bitsused to represent each element). Given that srca 488 and srcb 490 areeach 32-bit wide bit-vectors (e.g., stored in memory cells that arecoupled to 32 columns in memory) and that each element is represented byeight bits, each of srca 488 and srcb 490 comprise four elements (e.g.,32/8=4).

In a number of examples, the number of bits used to represent eachelement (e.g., the element width) can be a parameter provided by a hostand/or user, for instance. Also, in a number of embodiments, the elementcount of srca 488 and/or srcb 490 and/or the vector width correspondingto srca 488 and srcb 490 can be provided by a host and/or user as aparameter. As such, in a number of examples, the element width of thebit-vectors comprising srca 488 and/or srcb 490 can be determined basedon the vector width of srca 488 and srcb 490 and on the element count.For instance, given a vector width of 32 bits and an element count of 4,the element width would be 8 bits (e.g., 32/4=8).

The pseudocode referenced at reference number 3 (e.g., Obtain all TempRows) corresponds to initializing a number of groups of memory cells foruse as temporary storage rows during a comparison operation. That is,the number of groups of memory cells can be groups of cells coupled torespective access lines (e.g., rows) and can be used to temporarilystore data (e.g., as temporary storage) in association with performingthe comparison operation. For example, a first group of memory cells canstore a bit-vector referred to as “Row_Mask”, a second group of memorycells can store a bit-vector referred to as “Row_LowAct”, a third groupof memory cells can store a bit-vector referred to as “Row_Retained”, afourth group of memory cells can store a bit-vector referred to as“Row_Object”, a fifth group of memory cells can store a bit-vectorreferred to as “destc”, and a sixth group of memory cells can store abit-vector referred to as “destpc”. Embodiments are not limited to aparticular number of temporary storage rows. In a number of examples,each element pair that is being compared (e.g., a first element of srcaand a first element of srcb) can be associated with a different numberof bit-vectors corresponding to the rows that store Row_Mask 476,Row_LowAct 478, Row_Retained 480, Row_Object 482, destc 484, and/ordestpc 486. In a number of examples, the bit-vectors corresponding tothe rows that store temporary data are stored in memory cells coupled tothe same sense lines as the element pairs that are being compared.

For instance, Row_Mask 476 can be used to identify and/or isolateelements that are being compared and/or bits of the bit-vectorscorresponding to the elements that are being compared. Row_LowAct 478can be used to identify the elements of srca 488 and srcb 490 that willbe compared in the comparison operation. Row_Object 482 can be used toidentify a least significant bit in each element. Destc 484 and destpc486 can be used to identify the differences in srca 488 and srcb 490(e.g., the respective bit positions having different binary values).

The groups of memory cells corresponding to temporary storage rows 470may be oriented within memory 330 in a manner that facilitatesperformance of the comparison operation on the element pairs. Forexample, a plurality of groups of memory cells each storing thebit-vectors corresponding to respective temporary storage rows can becoupled to sense lines 305-0 to 305-31 in FIG. 3. Each group in theplurality of groups of memory cells can be coupled to a different accessline (e.g., an access line having cells coupled thereto that are notused to store the bit-vectors corresponding to the elements beingcompared).

Initiating Row_Mask 476, Row_LowAct 478, Row_Retained 480, andRow_Object 482 can include storing the bit-vector [00000000] in theplurality of groups of memory cells that store Row_Mask 476, Row_LowAct478, Row_Retained 480, and Row_Object 482.

The pseudocode referenced at reference number 4 (e.g., “Find MSB andstore in Comp_Comp, Row_Mask, Row_Retained”) is associated withdetermining the most significant bit (MSB) in srca 488 and/or srcb 490and storing a bit-vector indicating the MSB in particular groups ofmemory cells. The bit pattern indicating the most significant bit can bestored (e.g., as a bit-vector) in a group of memory cells used to storeRow_Mask 476 and in a group of memory cells used to store Row_Retained480. The bit pattern indicating the most significant bit can also bestored (e.g., as a latched bit-vector) in sensing circuitry (e.g.,compute components 331 and/or sense amplifiers 306 in FIG. 3). As anexample, a bit pattern comprising a “1” in a MSB position and all “Os”in the remaining bit positions can be used to indicate the MSB of srca488 and/or srcb 490. For example, if srca 488 and/or srcb 490 are 32-bitwide bit-vectors and are stored in memory cells coupled to sense lines305-0 to 305-31, then the 32-bit wide binary bit-vector [1000 0000 00000000 0000 0000 0000 0000] (e.g., hexadecimal bit-vector [80000000]) canbe used as the bit-vector indicating the MSB in srca 488 and/or srcb490. In a number of examples, the compute components 331-0 to 331-32 inFIG. 3 can latch the respective bits of the bit-vector [1000 0000 00000000 0000 0000 0000 0000]. For example, the compute component 331-0 canlatch a one (1) bit while the compute components 331-1 to 331-31 canlatch zero (0) bits.

The pseudocode referenced at reference number 5 (e.g., Find MSB byshifting right with fixed vector for each length in Comp_Comp) isassociated with determining a bit-vector that can indicate a MSBcorresponding to each of a number of elements represented by srca 488and/or srcb 490. The bit-vector used to indicate the MSBs correspondingto the number of elements can be determined by performing a number oflogical operations (e.g., a number of iterations of SHIFT operations andOR operations) on the bit-vector stored in the compute components (e.g.,331-0 to 331-31 in FIG. 3) and a group of memory cells that storeRow_Object 482 (e.g., whose corresponding bits can be stored in cellscoupled to a particular temporary storage row and to respective senselines 305-0 to 305-31). The SHIFT and OR iterations can result in abinary bit-vector [1000 0000, 1000 0000, 1000 0000] (e.g., thehexadecimal bit-vector [80808080]) that comprises a “1” at the bitpositions corresponding to the MSBs for each of the four elementsrepresented by srca 488 and/or srcb 490. The SHIFT operations can beright SHIFT operations; however, embodiments are not limited to thisexample. The SHIFT operations can be performed on Comp_Comp 431. The ORoperations can be performed on Row_Object 482 and Comp_Comp 431. Theresults of the SHIFT operations and the OR operations can be stored in agroup of memory cells that store Row_Object 482 and the computecomponents (e.g., 331-0 to 331-31 in FIG. 3).

The pseudocode referenced at reference number 6 (e.g., Right Shift forfixed length and store in Row_Object) is associated with determining abit-vector that can indicate a LSB corresponding to each of a number ofelements represented by srca 488 and/or srcb 490. A number of SHIFToperations can be performed on Comp_Comp 431 (e.g., the result of theSHIFT and OR operations performed in reference number 5) to identify theLSB corresponding to each of the number of elements. For example, if abinary bit-vector [1000 0000, 1000 0000, 1000 0000] identifies a mostsignificant bit for each element in srca 488 and/or srcb 490, then thebit-vector [000 0001, 0000 0001, 0000 0001] can identify the leastsignificant bit for each bit-vector that represents an element in srca488 and/or srcb 490. The least significant bit for each element in srca488 bit-vector and/or srcb 490 can be identified by performing a rightSHIFT operation a plurality of times equal to a vector length. Thehexadecimal bit-vector [01010101] is stored in a group of memory cellsthat store Row_Object 482. The bit-vector [01010101] bit-vectoridentifies (e.g., with a “1”) the least significant bit in each of theelements.

FIG. 4B illustrates a table showing the states of memory cells of anarray at a particular phase associated with performing a comparisonoperation in accordance with a number of embodiments of the presentdisclosure. FIG. 4B includes rows 470 that store temporary data thatinclude Row_Mask 476, Row_LowAct 478, Row_Retained 480, and Row_Object482 that are analogous to the rows 470 that store temporary data,Row_Mask 476, Row_LowAct 478, Row_Retained 480, and Row_Object 482 inFIG. 4A. FIG. 4B includes Comp_Comp 431 that is analogous to Comp_Comp431 in FIG. 4A. FIG. 4B also includes vector arguments 472 that areanalogous to vector arguments 472 in FIG. 4A. The vector arguments 472can include srca 488, srcb 490, dest 492, and/or a dest+1 bit-vector 494that are analogous to vector arguments 472, srca 488, srcb 490, dest492, and/or dest+1 494 in FIG. 4A. FIG. 4B includes scalar integersdestc 484 and destpc 486 that are analogous to scalar integers destc 484and destpc 486 in FIG. 4A. FIG. 4B shows the result of a number ofinstructions performed in a comparison stage.

The pseudocode referenced at reference number 7 (e.g., For each Vectorelement), corresponds to a “For” loop described via the pseudocodereferenced at reference numbers 7.a to 7.z.i. As such, the “For” loopcorresponding to reference number 7 involves performing a number ofiterations of operations. Each iteration of operations of the number ofiterations of operations corresponds to a particular element pair beingcompared. For instance, a first iteration of operations shown aspseudocode 7.a to 7.z.i is performed in association with comparing thefirst element pair, a second iteration of operations shown as pseudocode7.a to 7.z.i is performed in association with comparing the secondelement pair, etc.

At reference number 7.a (e.g., Create Full Row_Mask for the element withbits enabled), a full row mask is created. A full row mask is defined asa mask that includes a specific bit pattern for a particular elementand/or a particular plurality of elements. The specific bit pattern caninclude all ones (e.g, “1”) or all zeros (e.g., “0”). For example,during a first iteration (e.g., an iteration corresponding to a firstelement pair) of the “For” loop associated with reference number 7.a, abinary bit-vector [1111 1111, 0000 0000, 0000 0000] (e.g., a hexadecimalbit-vector [ff000000]) is created and stored in a group of memory cellsthat store Row_Mask 476. Row_Mask 476 can be used to isolate an elementin srca 488 and/or srcb 490 during a comparison operation. Thebit-vector [ff000000] can also identify that a current comparisonoperation compares a first element from srca 488 and a first elementfrom srcb 490. The full row mask can be created via a plurality of SHIFToperation that are performed on Row_Mask 476 and a plurality of ORoperations that are performed on Comp_Comp 431 and Row_Mask 476.

At reference number 7.b (e.g., Right Shift Row_Retained to the fixedlength of the element), Row_Retained 480 is stored in a group of computecomponents 331 in FIG. 3 (e.g., the Row_Retained bit-vector is read).That is Comp_Comp 431 can be equal to Row_Retained 480. A SHIFToperation can be performed on Comp_Comp 431 to identify the next elementpair from srca 488 and srcb 490 that will be compared. For example, aright SHIFT operation can be performed on Row_Retained (e.g., binarybit-vector [1000 0000, 0000 0000, 0000 0000, 0000 0000]) that identifiesthat a first element pair from srca 488 and srcb 490 will be compared.The results of the right SHIFT operation (e.g., hexadecimal bit-vector[00800000]) can be stored in a third temporary group of memory cellsthat store Row_Retained 480.

At reference number 7.c (e.g., Load srca in Comp_Comp), srca 488 can bestored in sensing circuit. For example, srca 488 (e.g., a hexadecimalbit-vector [0309020c]) can be stored in the compute components 331and/or the sense amplifiers 306 in FIG. 3.

At reference number 7.d (e.g., Do Comp_Comp AND operation with srcb), anAND operation can be performed on Comp_Comp 431 and srcb 490 that isstored in a group of memory cells coupled to access line 304-1. The ANDoperation can be performed to identify common bits with a value equal toone (1) between Comp_Comp 431 (e.g., srca 488) and srcb 490. The result(e.g., a hexadecimal bit-vector [0301000c]) of the AND operation can bestored in the sensing circuitry (e.g., compute components 331 and/orsense amplifier 306).

At reference number 7.e (e.g., Store Inverse of Comp_Comp inRow_LowAct), an INVERT operation can be performed on Comp_Comp 431(e.g., hexidecimal bit-vector [0301000c] which is the results of theprevious AND operation) to identify bits that are not shared betweensrca 488 and srcb 490. The result (e.g., bit-vector [fcfefff3]) of theINVERT operation can be stored in the group of memory cells that storeRow_LowAct 478.

At reference number 7.f (e.g., Load Row_LowAct in Comp_Comp), Row_LowAct478 (e.g., a bit-vector [fcfefff3]) is stored in the sensing circuitry.At reference number 7.g (e.g., Do Comp_Comp AND operation with srca), anAND operation is performed on Comp_Comp 431 (e.g., Row_LowAct 478) andsrca 488. The AND operation can be performed on Comp_Comp 431 (e.g., abit-vector [fcfefff3]) and srca 488 (e.g., a bit-vector [0309020c]) toidentifies indexes of bits in srca 488 that have a value of one (1) andassociated bits in srcb 490 that have a value of zero (0). The result(e.g., a bit-vector [00080200]) of the AND operation is stored in thesensing circuitry. The result identifies that a bit with an index,(e.g., given that a first index identifies a least significant bit)equal to four (4) in a second element in srca 488 has a one (1) valueand that a bit with an index equal to four (4) in an associated elementin srcb 490 has a zero (0) value. The result also identifies that a bitwith an index, (e.g., given that a first index identifies a leastsignificant bit) equal to two (2) in a third element in srca 488 has aone (1) value and that a bit with an index equal to two (2) in anassociated element in srcb 490 has a zero (0) value. The results of theAND logical operation can be stored in the sensing circuitry.

At reference number 7.h (e.g., Do Comp_Comp AND operation withRow_Mask), an AND operation is performed on Comp_Comp 431 (e.g., ahexadecimal bit-vector [00080200]) and on Row_Mask 476 (e.g., abit-vector [ff000000]) to isolate the identified indexes that areassociated with a current comparison operation. The results (e.g., abit-vector [00000000] bit-vector) of the AND operation can be stored inthe sensing circuitry.

At reference number 7.i (e.g., Do Comp_Comp OR operation with dest), anOR operation is performed on Comp_Comp 431 (e.g., a hexadecimalbit-vector [00000000]) and dest 792 (e.g., a bit-vector [00000000]). Theresult (e.g., a bit-vector [00000000]) of the OR operation is stored inthe sensing circuitry. At reference number 7.j (e.g., Store Comp_Comp indest), Comp_Comp 431 (e.g., a bit-vector [00000000]) is stored in agroup of memory cells that store dest 492.

At reference number 7.k (e.g., Load Row_LowAct in Comp_Comp), Row_LowAct478 (e.g., a bit-vector [fcfefff3]) is stored in the sensing circuitry.At reference number 7.1 (e.g., Do Comp_Comp AND operation with srcb), anAND operation is performed on a Comp_Comp 431 (e.g., a bit-vector[fcfefff3]) and on srcb 490 (e.g., a bit-vector [0705080c]). The ANDoperation is performed to identify indexes of bits in srcb 490 that havea value of one (1) and associated bits in srca 488 that have a value ofzero (0). The result (e.g., a bit-vector [04040800]) is stored in thesensing circuitry.

At reference number 7.m (e.g., Do Comp_Comp AND operation withRow_Mask), an AND operation is performed on Comp_Comp 431 (e.g., abit-vector [04040800]) and on Row_Mask 476 (e.g., a bit-vector[ff000000]) to isolate the identified indexes that are associated with acurrent comparison operation. The result (e.g., a bit-vector [04000000])is stored in the sensing circuitry. At reference number 7.n (e.g., DoComp_Comp OR operation with dest+1), an OR operation is performed onComp_Comp 431 (e.g., a bit-vector [04000000]) and dest+1 494 (e.g., abit-vector [00000000]). At reference number 7.0 (e.g., Store Comp_Compin dest+1), the result (e.g., a bit-vector [04000000]) of the ORoperation is stored in the group of memory cells that store dest+1 494.

At reference number 7.p (e.g., Load dest in Comp_Comp), dest 492 (e.g.,a bit-vector [00000000]) is stored in the sensing circuitry. Atreference number 7.q (e.g., Do Comp_Comp AND operation with Row_Mask),an AND operation is performed on Comp_Comp 431 (e.g., a bit-vector[00000000]) and Row_Mask 476 (e.g., a bit-vector [FF000000]) to isolatethe bits in Comp_Comp 431 that are associated with the current compareoperation. The result of the AND operation is stored in the sensingcircuitry. At reference number 7.r (e.g., Store Comp_Comp inRow_LowAct), Comp_Comp 431 (e.g., a bit-vector [00000000]) is stored inthe group of memory cells that store Row_LowAct 478.

At reference number 7.s (For Vector fixed width), a “For” loop isexecuted. The “For” loop iterates through the indexes associated with anelement width. A number of operations are performed (e.g., operationsassociated with reference number 7.s.i. to 7.s.vi.) for each index. The“For” loop iterations through the indexes associated with an elementwidth. For example, if an element is represented by a bit-vector witheight bits (e.g., element width), then the “For” loop can iterate eighttimes, each iteration incrementing the index by one. During a firstiteration of the “For” loop an index will have a value of one (1),during a second iteration of the “For” loop an index will have a valueof two (2), . . . , and during an eight iteration of the “For” loop anindex will have a value of eight (8). The “For” loop will conclude(e.g., break) after the eighth iteration.

At reference number 7.s.i (e.g., Do Comp_Comp AND operation withRow_Mask), an AND operation is performed on Comp_Comp (e.g., abit-vector [00000000]) and Row_Mask 476 (e.g., a bit-vector [ff000000]).The results (e.g., a bit-vector [00000000]) of the AND operation isstored in the sensing circuitry. At reference number 7.s.ii (e.g., StoreComp_Comp in Row_LowAct), Comp_Comp 431 (e.g., a bit-vector [00000000])is stored in the group of memory cells that store Row_LowAct 478.

At reference number 7.s.iii. (Do Comp_Comp AND operation withRow_Object), an AND operation is performed on Comp_Comp 431 (e.g., abit-vector [00000000]) and on Row_Object 482 (e.g., a bit-vector[01010101]). The result (e.g., a bit-vector [00000000]) of the ANDoperation is stored in the sensing circuitry.

At reference number 7.s.iv. (e.g., Store return value of BLOCKORoperation into scalar integer destc), a BLOCKOR operation is performedon Comp_Comp 431. The result (e.g., [00000000]) of the BLOCKOR operationis stored in memory that is associated with the control circuitry andthat store destc 484. As used herein, the BLOCKOR operation can beperformed to determine whether one or more bits of a bit-vector storedin the sensing circuitry are a particular value (e.g., whether any ofthe bits stored in the sensing circuitry are a one “1” bit). The BLOCKORoperation can be performed using an I/O line 334 and a secondary senseamplifier 312.

The BLOCKOR operation is performed to determine a most significant bitindex of bits in srca 488 that have a value of one (1) and associatedbits in srcb 490 that have a value of zero (0). The result of theBLOCKOR operation is stored as an scalar integer memory that isassociated with control circuitry and that stores destc 484. The BLOCKORoperation is performed on the bits of Comp_Comp that are associated witha number of indexes. The number of indexes are indexes that the “For”loop in reference number 7.s iterates. For example, the BLOCKORoperation is performed during each iteration of the “For” loopreferenced in reference number 7.s and is only performed on the iteratedindexes of the “For” loop. For example, during a first iteration of the“For” loop referenced in reference number 7.s the BLOCKOR operation isperformed on the least significant bit in Comp_Comp 431. During thesecond iteration of the “For” loop reference in reference number 7.s theBLOCKOR operation is performed on two least significant bits (e.g., bitswith an index equal to zero (0) and one (1) in Comp_Comp 431). During aneighth iteration of the “For” loop referenced in reference number 7.sthe BLOCKOR operation is performed on all the bits in Comp_Comp 431.

In a number of embodiments, a BLOCKOR operation can be performed inassociation with determining if the memory cells coupled to one or more(e.g., any) particular sense line store a data pattern that matches thetarget data pattern. For example, knowing whether one or more matches tothe target data pattern are stored in an array may be usefulinformation, even without knowing which particular sense line(s) iscoupled to cells storing the matching data pattern. In such instances,the determination of whether any of the sense lines are coupled to cellsstoring a match of the target data pattern can include charging (e.g.,precharging) a local I/O line (e.g., local I/O line 334) coupled to asecondary sense amplifier (e.g., 312) to a particular voltage. The I/Oline (e.g., 334) can be precharged via control circuitry such as controlcircuitry 140 shown in FIG. 1 and/or sensing circuitry such as circuitry150 shown in FIG. 1, for instance, to a voltage such as a supply voltage(e.g., Vcc) or a ground voltage (e.g., 0V).

In performing a BLOCKOR operation (which may be referred to as an“AccumulatorBlockOr”), the column decode lines (e.g., 310-1 to 310-W)coupled to the selected sensing circuitry (e.g., sense amplifiers 306and/or compute components 331) can be activated in parallel (e.g., suchthat respective transistors 308-1 to 308-V are turned on) in order totransfer the voltages of the components of the sensing circuitry (e.g.,sense amplifiers 306 and/or compute components 331) to the local I/Oline (e.g., 334). The secondary sense amplifier (e.g., SSA 314) cansense whether the precharged voltage of the local I/O line changes(e.g., by more than a threshold amount) responsive to activation of thecolumn decode lines.

For instance, if the I/O line 234 is precharged to a ground voltage andone or more of the selected compute components (e.g., 33 1-1 to 331-X)stores a logic 1 (e.g., 0V) to represent a match, then the SSA 312 cansense a pull up (e.g., increase) of the voltage on I/O line 334 todetermine whether any stored data pattern matches the target datapattern (e.g., whether at least one of the accumulators stores a “1”).Alternatively, if the I/O line 334 is precharged to Vcc and one or moreof the selected sensing circuitry components (e.g., accumulators) storesa logic 0 (e.g., Vcc) to represent a match, then the SSA 312 can sense apull down (e.g., decrease) of the voltage on I/O line 334 to determinewhether any stored data pattern matches the target data pattern (e.g.,whether at least one of the accumulators stores a “0”).

In a number of examples, the determination of whether the sensingcircuitry coupled to selected column decode lines stores a particulardata value (e.g., a match data value of “1”) is effectively performing alogic “OR” operation. In this manner, voltages corresponding to datastored in sensing circuitry can be transferred, in parallel, to thelocal I/O line 334 and sensed by SSA 312 as part of a BLOCKOR operation.Embodiments of the present disclosure are not limited to particularprecharge voltages of local I/O line 334 and/or to particular voltagevalues corresponding to logic 1 or logic 0.

At reference number 7.s.v (Load Row_LowAct in Comp_Comp), Row_LowAct 478is stored in the sensing circuitry. At reference number 7.s.vi (ShiftRight), a SHIFT operation is performed on Comp_Comp 431 (e.g., abit-vector [00000000]). The SHIFT operation can be a right SHIFToperation. The results of the SHIFT operation are stored in the sensingcircuitry.

At reference number 7.t (Load dest+1 in Comp_Comp), dest+1 494 is storedin the sensing circuitry. At reference number 7.u (e.g., Do Comp_CompAND operation with Row_Mask), an AND operation is performed on Comp_Comp(e.g., a bit-vector [04000000]) 431 and Row_Mask 476 (e.g., a bit-vector[ff000000]). The result [04000000] is stored in the sensing circuitry.At reference number 7.v (e.g., Store Comp_Comp in Row_LowAct), Comp_Comp431 (e.g., a bit-vector [04000000]) is stored in the group of memorycells that store Row_LowAct 478.

At reference number 7.w (e.g., For Vector fixed width), a “For” loop isperformed. The “For” loop referenced in reference number 7.w isanalogous to the “For” loop referenced in reference number 7.s.Reference numbers 7.w.i to 7.w.iii are also analogous to referencenumbers 7.s.i to 7.s.iii.

At reference number 7.w.i (e.g., Do Comp_Comp AND operation withRow_Mask), an AND operation is performed on Comp_Comp 431 (e.g., thebit-vector [04000000]) and Row_Mask 476 (e.g., the bit-vector[ff000000]). The result (e.g., [04000000]) of the AND operation isstored in the sensing circuitry. At reference number 7.w.ii (e.g., StoreComp_Comp in Row_LowAct), the result of the AND operation is stored inthe group of memory cells that store Row_LowAct 478.

At reference number 7.w.iii (e.g., Do Comp_Comp AND operation withRow_Object), an AND operation is performed on Comp_Comp 431 (e.g., abit-vector [04000000]) and Row_Object 482 (e.g., e.g., a bit-vector[01010101]). The result (e.g., [01000000]) of the AND operation isstored in the sensing circuitry.

At reference number 7.w.iv (e.g., Store result value of BLOCKORoperation into scalar integer destpc), a BLOCKOR operation is performedon Comp_Comp 431 (e.g., a bit-vector [01000000]). The result (e.g., 3)of the BLOCKOR operation is stored in the group of memory cells thatstore destpc 486.

At reference number 7.w.v (e.g., Load Row_LowAct in Comp_Comp),Row_LowAct 478 is stored in the sensing circuitry. At reference number7.w.vi (e.g., Shift Right), A SHIFT operation is performed on Comp_Comp431 (e.g., a bit-vector [01000000]). The result (e.g., a bit-vector[00000000]) of the SHIFT operation is stored in the sensing circuitry.

At reference number 7.x (e.g., if destc>destpc), it is determined thatdestc 484 (e.g., a bit-vector [0]) is not greater than destpc 486 (e.g.,a bit-vector [3]). If destc 484 were greater than destpc 486, then anumber of operations referenced in reference numbers 7.x.i to 7.x.iiwould be performed.

For example, at reference number 7.x.i (e.g., Populate dest withRow_Mask), dest 492 is stored in the sensing circuitry. An OR operationis performed on Comp_Comp 431 and Row_Mask 476. The result of the ORoperation is stored in the group of memory cells that store dest 492.

At reference number 7.x.ii (e.g., Populate dest+1 with InverseRow_Mask), an INVERT operation is performed on Row_Mask 476. The resultof the INVERT operation is stored in the sensing circuitry. An ANDoperation is performed on Comp_Comp 431 and dest+1 494. The result ofthe AND operation is stored in the group of memory cells that storedest+1 494.

At reference number 7.y (e.g., else If destpc>destc), it is determinedthat destpc 486 (e.g., a scalar integer 3) is greater than destc 484(e.g., a scalar integer 0). A number of operations referenced inreference numbers 7.y.i to 7.y.ii are performed based on thedetermination that destpc 486 is greater than destc 484.

At reference number 7.y.i (Populate dest+1 with Row_Mask), dest+1 494 isstored in the sensing circuitry. An OR operation is performed on dest+1494 and Row_Mask 476. The result (e.g., a bit-vector [ff000000]) of theOR operation is stored in the group of memory cells that store dest+1494 to update dest+1 494.

At reference number 7.y.ii (Populate dest with Inverse Row_Mask), anINVERToperation is performed on Row_Mask 476. An AND operation isperformed on Comp_Comp 431 and dest 492. The result (e.g., a bit-vector[00000000]) of the AND operation is stored in the group of memory cellsthat store dest 492 to update dest 492. The bold font used in the abovebit-vectors describe the portion of the bit-vector (e.g., dest 492and/or dest+1 494) that is updated.

The bit-vector [ff000000] (e.g., dest+1 494) indicates that the firstelement in srcb 490 is greater than the first element in srca 488. Thebits that are associated with “ff” in dest+1 494 have a number ofindexes. The indexes can identify associated elements in srca 488 andsrcb 490 that form an element pair. The “ff” in dest+1 494 indicates theidentified element in srcb 490 is greater than the identified element insrca 488. The [00000000] dest bit-vector 492 indicates that the firstelement in srca 488 can be less than the first element in srcb 490 orequal to the first element in srcb 490.

At reference number 7.z (e.g., else), it is determined whether destc 484is not equal to destpc 486 and whether destpc 486 is not equal to destc484. That is, at reference number 7.z it is determined whether destc 484is equal to destpc 486. If destc 484 is equal to destpc 486, then anumber of operations are performed at reference number 7.z.i. The numberof operations can include performing an INVERT operation on Row_Mask 476and storing the result of the INVERT operation in the sensing circuitry.The number of operations can also include performing an AND operation onComp_Comp 431 and dest 492. The result of the AND operation can bestored in the group of memory cells that store dest 492. The number ofoperations can also include performing an AND operation on Comp_Comp 431and dest+1 494. The result of the AND operation can be stored in thegroup of memory cells that store dest+1 494.

FIG. 4C illustrates a table showing the states of memory cells of anarray at a particular phase associated with performing a comparisonoperation in accordance with a number of embodiments of the presentdisclosure. FIG. 4C includes rows 470 that store temporary data thatinclude Row_Mask 476, Row_LowAct 478, Row_Retained 480, and Row_Object482 that are analogous to the rows 470 that store temporary data,Row_Mask 476, Row_LowAct 478, Row_Retained 480 and Row_Object 482 inFIGS. 4A 4B. FIG. 4C includes the Comp_Comp 431 that are analogous toComp_Comp 431 in FIG. 4A and FIG. 4B. FIG. 4C also includes vectorarguments 472 that are analogous to vector arguments 472 in FIGS. 4A and4B. The vector arguments 472 can include srca 488, srcb 490, dest 492,and/or dest+1 494 that are analogous to vector arguments 472, srca 488,srcb 490, dest 492, and/or dest 494 in FIGS. 4A and 4B. FIG. 4c alsoincludes scalar integers destc 484, and/or destpc 486 that are analogousto scalar integers destc 484 and dest pc 486 in FIGS. 4A and 4B.

FIG. 4C shows the state of a number of memory cells during a comparisonphase that follows the comparison phase in FIG. 4B. That is, FIG. 4Cshows the state of the number of memory cells during a second iterationof the “For” loop referenced in reference number 7.

At reference number 7.a, a bit-vector [00ff0000] is created. Thebit-vector [00ff0000] in a group of memory cells that store Row_Mask476. The Row_Mask 476 (e.g., the bit-vector [00ff0000]) identifies thata current comparison operation compares a second element from srca 488and a second element from srcb 490.

At reference number 7.b, a [00008000] bit-vector is stored in thesensing circuitry and is stored in a group of memory cells that storeRow_Retained 480. The bit-vector [00008000] identifies the next elementsthat are to be compared in a subsequent iteration of the “For” loopreferenced in reference number 7.

At reference number 7.c, srca 488 is stored in the sensing circuitry. Atreference number 7.d the result (e.g., [0301000c]) of an AND operationperformed on srca 488 and srcb 490 is stored in the sensing circuitry.

At reference number 7.e, an INVERT operation is performed on thebit-vector [0301000c]. The result of the INVERT operation is abit-vector [fcfefff3]. The [fcfefff3] bit-vector is stored in a group ofmemory cells that store Row_LowAct 478. At reference number 7.f., thebit-vector [fcfefff3] (e.g., Row_LowAct 478) is stored in the sensingcircuitry. At reference number 7.g., an AND operation is performed onComp_Comp 431 (e.g., a bit-vector [fcfefff3]) and srca 488 (e.g., abit-vector [0309020c]). The result (e.g., a bit-vector [00080200]) of isstored in the sensing circuitry.

At reference number 7.h, an AND operation is performed on Comp_Comp(e.g., a bit-vector [00080200]) and on Row_Mask 476 (e.g., a bit-vector[00ff0000]). The result (e.g., a bit-vector [00080000]) is stored in thesensing circuitry. At reference number 7.i, an OR operation is performedon Comp_Comp 431 (e.g., a bit-vector [00080000]) and dest 492 (e.g., abit-vector [00000000]). The result (e.g., a bit-vector [00080000]) ofthe OR operation is stored in the sensing circuitry.

At reference number 7.j, the result (e.g., a bit-vector [00080000]) ofthe OR operation is stored in the group of memory cells that store dest492. At reference number 7.k, Row_LowAct 478 (e.g., a bit-vector[fcfefff3]) is stored in the sensing circuitry. At reference number 7.1,an AND operation is performed on Comp_Comp 431 (e.g., a bit-vector[fcfefff3]) and on srcb 490 (e.g., a bit-vector [0705080c]). The result(e.g., a bit-vector [04040800]) is stored in the sensing circuitry.

At reference number 7.m, an AND operation is performed on the bit-vector[04040800] (e.g., Comp_Comp 431) and bit-vector [00ff0000] (e.g.,Row_Mask 476). The result (e.g., a bit-vector [00040000]) is stored inthe sensing circuitry. At reference number 7.n, an OR operation isperformed on the bit-vector [00040000] (e.g., Comp_Comp 431) and thebit-vector [ff000000] (e.g., dest+1 494). At reference number 7.o, theresult (e.g., a bit-vector [ff040000]) is stored in dest+1 494.

At reference number 7.p, dest 492 (e.g., [00080000]) is stored in thesensing circuitry. At reference number 7.q, an AND operation isperformed on the bit-vector [00080000] (e.g., Comp_Comp 431) and abit-vector [00ff0000] (e.g., Row_Mask 476). At reference number 7.r, theresult (e.g., a bit-vector [00080000]) of the AND operation is stored inthe group of memory cells that store Row_LowAct 478.

At reference number 7.s, a “For” loop is performed. The “For” loopincrements a bit index after each iteration. The index begins with a onevalue and is incremented until the “For” loop breaks. The “For” loopcontinues while the index is less or equal to the element width.Reference numbers 7.s.i to 7.s.vi show a state of a number of memorycells after the last iteration of the “For” loop.

At reference number 7.s.i., an AND operation is performed on abit-vector [00080000] (e.g., Comp_Comp 431) and a bit-vector [000ff000](e.g., Row_Mask 476). The result (e.g., a bit-vector [00080000]) of theAND operation is stored in the sensing circuitry. At reference number7.s.ii., the results of the AND operation are stored in the group ofmemory cells that store Row_LowAct 478.

At reference number 7.s.iii, an AND operation is performed on thebit-vector [00080000] (e.g., Comp_Comp 431) and a bit-vector [01010101](e.g., Row_Object 482). The result (e.g., a bit-vector [00000000]) isstored in the sensing circuitry. At reference number 7.s.iv, a BLOCKORoperation is performed on Comp_Comp 431. The result (e.g., 4) of theBLOCKOR operation is stored memory that is associated with controlcircuitry and that stores destc 484.

At reference number 7.s.v, Row_LowAct 478 is stored in sensingcircuitry. At reference number 7.s.vi., a SHIFT operation is performedon the bit-vector [00080000] (e.g., Comp_Comp 431). The result of theSHIFT operation is stored in the sensing circuitry.

At reference number 7.t, a bit-vector [ff040000] (e.g., dest+1 494] isstored in the sensing circuitry. At reference number 7.u, an ANDoperation is performed on a bit-vector [ff040000] (e.g., Comp_Comp 431)and the bit-vector [00ff0000] (e.g., Row_Mask 476). The result (e.g., abit-vector [00040000]) is stored in the sensing circuitry. At referencenumber 7.v, the result (e.g., a bit-vector [00040000]) is stored in thegroup of memory cells that store Row_LowAct 478.

Reference numbers 7.w.i to 7.w.vi reference a number of operationsperformed in a “For” loop (e.g., 7.w). At reference number 7.w.i, an ANDoperation is performed on the bit-vector [00040000] (e.g., Comp_Comp)and a bit-vector [00ff0000] (e.g., Row_Mask 476). The result (e.g., abit-vector [00040000]) of the AND operation is stored in the sensingcircuitry 431. At reference number 7.w.ii, the result (e.g., abit-vector [00040000]) of the AND operation is stored in the group ofmemory cells that store Row_LowAct 478. At reference number 7.w.iii., anAND operation is performed on the bit-vector [00040000] (e.g.,Comp_Comp) and a bit-vector [01010101] (e.g., Row_Object 482). Theresult (e.g., [00000000]) of the AND operation is stored in the sensingcircuitry. At reference number 7.w.iv, a BLOCKOR operation is performedon a bit-vector [00000000](e.g., Comp_Comp). The result (e.g., 3) of theBLOCKOR operation is stored in memory that is associated with controlcircuitry and that stores destpc 486. At reference number 7.w.v,Row_LowAct 478 is stored in the sensing circuitry. At reference number7.w.vi, A SHIFT operation (e.g., a right SHIFT operation) is performedon the bit-vector [00000000] (e.g., Comp_Comp). The result (e.g., abit-vector [00000000]) of the SHIFT operation is stored in the sensingcircuitry.

At reference number 7.x, it is determined that destc 484 (e.g., [4]) isgreater than destpc 486 (e.g., [3]). At reference number 7.x.i, abit-vector [00080000] (e.g., dest 492) is stored in the sensingcircuitry and an OR operation is performed on the bit-vector [00080000](e.g., Comp_Comp 431) and a bit-vector [00ff0000] (e.g., Row_Mask 476).As a result (e.g., a bit-vector [00ff0000]) is stored in a group ofmemory cells that store dest 492. That is, dest 492 is updated (e.g.,[00ff0000]). At reference number 7.x.ii, an INVERT operation isperformed on the bit-vector [00ff0000]. The results (e.g., a bit-vector[ff00ffff]) is stored in the sensing circuitry. An AND operation isperformed on the bit-vector [ff00ffff] (e.g., Comp_Comp 431) and abit-vector [ff040000] (e.g., dest+1 494). The result (e.g., a bit-vector[ff000000]) is stored in the group of memory cells that store dest+1494. That is, dest+1 494 is updated. The bit-vector [00ff0000] (e.g.,dest 492) indicates that the second element in srca 488 is greater thanthe second element in srcb 490. The bit-vector [ff000000] dest+1 494indicates that the second element in srcb 490 is less than or equal tothe second element in srca 488.

At reference number 7.y, it is determined that destpc 486 is not greaterthan destc 484. At reference number 7.z, it is determined that destc 484is not equal to destpc 486.

The final two iteration of the “For” loop referenced in reference number7 are not shown. After a third iteration of the “For” loop, dest 492 hasa value equal to a bit-vector [00ff0000] and dest+1 494 has a valueequal to the bit-vector [ff00ff00]. That is, dest+1 494 indicates thatthe third element in srcb 490 is greater than the third element in srca488.

After a fourth iteration of the “For” loop reference in reference number7, dest 492 has a value equal to the bit-vector [00ff0000] and dest+1has a value equal to the bit-vector [ff00ff00]. That is, dest 492 anddest+1 494 together indicate that the fourth element in srca 488 isequal to the fourth element in srcb 490. The “00” bits with a same indexin both dest+1 494 and dest 492 indicate that the corresponding elementsfrom srcb 490 and srca 488 are equal.

At reference number 8, the memory cells that store Row_Mask 476,Row_LowAct 478, Row_Retained 480, Row_Object 482, srca 488, and/or srcb490 can be released. As used herein, releasing memory cells can make thememory cells available for storing data that is associated with adifferent instance of a comparison operation and/or logical operationsnot associated with a comparison operation.

Embodiments however, are not limited to the order of the sequence ofinstructions in the pseudocode in this example. For example, a number ofoperations reference in reference numbers 7.t. to 7.w.vi. can beperformed before a number of operations reference in reference numbers7.p. to 7.s.vi. are performed.

The functionality of the sensing circuitry 250 of FIG. 2A is describedbelow and summarized in Table 1 below with respect to performing logicaloperations and initially storing a result in the sense amplifier 206.Initially storing the result of a particular logical operation in theprimary latch of sense amplifier 206 can provide improved versatility ascompared to previous approaches in which the result may initially residein a secondary latch (e.g., accumulator) of a compute component 231, andthen be subsequently transferred to the sense amplifier 206, forinstance.

TABLE 1 Operation Accumulator Sense Amp AND Unchanged Result ORUnchanged Result NOT Unchanged Result SHIFT Unchanged Shifted Data

Initially storing the result of a particular operation in the senseamplifier 206 (e.g., without having to perform an additional operationto move the result from the compute component 231 (e.g., accumulator) tothe sense amplifier 206) is advantageous because, for instance, theresult can be written to a row (of the array of memory cells) or backinto the accumulator without performing a precharge cycle (e.g., on thecomplementary data lines 205-1 (D) and/or 205-2 (D_)).

FIG. 5 illustrates a timing diagram associated with performing a numberof logical operations using sensing circuitry in accordance with anumber of embodiments of the present disclosure. FIG. 5 illustrates atiming diagram associated with initiating an AND logical operation on afirst operand and a second operand. In this example, the first operandis stored in a memory cell coupled to a first access line (e.g., ROW X)and the second operand is stored in a memory cell coupled to a secondaccess line (e.g., ROW Y). Although the example refers to performing anAND on data stored in cells corresponding to one particular column,embodiments are not so limited. For instance, an entire row of datavalues can be ANDed, in parallel, with a different row of data values.For example, if an array comprises 2,048 columns, then 2,048 ANDoperations could be performed in parallel.

FIG. 5 illustrates a number of control signals associated with operatingsensing circuitry (e.g., 250) to perform the AND logical operation. “EQ”corresponds to an equilibrate signal applied to the sense amp 206, “ROWX” corresponds to an activation signal applied to access line 204-X,“ROW Y” corresponds to an activation signal applied to access line204-Y, “Act” and “RnIF” correspond to a respective active positive andnegative control signal applied to the sense amp 206, “LOAD” correspondsto a load control signal (e.g., LOAD/PASSD and LOAD/PASSDb shown in FIG.2A), and “AND” corresponds to the AND control signal shown in FIG. 2A.FIG. 5 also illustrates the waveform diagrams showing the signals (e.g.,voltage signals) on the digit lines D and D_ corresponding to sense amp206 and on the nodes S1 and S2 corresponding to the compute component231 (e.g., Accum) during an AND logical operation for the various datavalue combinations of the Row X and Row Y data values (e.g., diagramscorrespond to respective data value combinations 00, 10, 01, 11). Theparticular timing diagram waveforms are discussed below with respect tothe pseudo code associated with an AND operation of the circuit shown inFIG. 2A.

An example of pseudo code associated with loading (e.g., copying) afirst data value stored in a cell coupled to row 204-X into theaccumulator can be summarized as follows:

Copy Row X into the Accumulator:      Deactivate EQ      Open Row X     Fire Sense Amps (after which Row X data resides in the sense amps)     Activate LOAD (sense amplifier data (Row X) is transferred to nodesS1 and S2 of the Accumulator and resides there dynamically)     Deactivate LOAD      Close Row X      Precharge

In the pseudo code above, “Deactivate EQ” indicates that anequilibration signal (EQ signal shown in FIG. 5) corresponding to thesense amplifier 206 is disabled at t₁ as shown in FIG. 5 (e.g., suchthat the complementary data lines (e.g., 205-1 (D) and 205-2 (D_) are nolonger shorted to V_(DD)/2). After equilibration is disabled, a selectedrow (e.g., ROW X) is enabled (e.g., selected, opened such as byactivating a signal to select a particular row) as indicated by “OpenRow X” in the pseudo code and shown at t₂ for signal Row X in FIG. 5.When the voltage signal applied to ROW X reaches the threshold voltage(Vt) of the access transistor (e.g., 202-2) corresponding to theselected cell, the access transistor turns on and couples the data line(e.g., 205-2 (D_)) to the selected cell (e.g., to capacitor 203-2) whichcreates a differential voltage signal between the data lines.

After Row X is enabled (e.g., activated), in the pseudo code above,“Fire Sense Amps” indicates that the sense amplifier 206 is enabled toset the primary latch and subsequently disabled. For example, as shownat t₃ in FIG. 5, the ACT positive control signal (e.g., 265 shown inFIG. 2B) goes high and the RnIF negative control signal (e.g., 228 shownin FIG. 2B) goes low, which amplifies the differential signal between205-1 (D) and D_ 205-2, resulting in a voltage (e.g., V_(DD))corresponding to a logic 1 or a voltage (e.g., GND) corresponding to alogic 0 being on data line 205-1 (D) (and the voltage corresponding tothe other logic state being on complementary data line 205-2 (D_)). Thesensed data value is stored in the primary latch of sense amplifier 206.The primary energy consumption occurs in charging the data lines (e.g.,205-1 (D) or 205-2 (D_)) from the equilibration voltage V_(DD)/2 to therail voltage V_(DD).

The four sets of possible sense amplifier and accumulator signalsillustrated in FIG. 5 (e.g., one for each combination of Row X and Row Ydata values) shows the behavior of signals on data lines D and D_. TheRow X data value is stored in the primary latch of the sense amp. Itshould be noted that FIG. 2A shows that the memory cell includingstorage element 202-2, corresponding to Row X, is coupled to thecomplementary data line D_, while the memory cell including storageelement 202-1, corresponding to Row Y, is coupled to data line D.However, as can be seen in FIG. 2A, the charge stored in memory cell202-2 (corresponding to Row X) corresponding to a “0” data value causesthe voltage on data line D_ (to which memory cell 202-2 is coupled) togo high and the charge stored in memory cell 202-2 corresponding to a“1” data value causes the voltage on data line D_ to go low, which isopposite correspondence between data states and charge stored in memorycell 202-2, corresponding to Row Y, that is coupled to data line D.These differences in storing charge in memory cells coupled to differentdata lines is appropriately accounted for when writing data values tothe respective memory cells.

After firing the sense amps, in the pseudo code above, “Activate LOAD”indicates that the LOAD control signal goes high as shown at t₄ in FIG.5, causing load/pass transistors 218-1 and 218-2 to conduct. In thismanner, activating the LOAD control signal enables the secondary latchin the accumulator of the compute component 231. The sensed data valuestored in the sense amplifier 206 is transferred (e.g., copied) to thesecondary latch. As shown for each of the four sets of possible senseamplifier and accumulator signals illustrated in FIG. 5, the behavior atinputs of the secondary latch of the accumulator indicates the secondarylatch is loaded with the Row X data value. As shown in FIG. 5, thesecondary latch of the accumulator may flip (e.g., see accumulatorsignals for Row X=“0” and Row Y=“0” and for Row X=“1” and Row Y=“0”), ornot flip (e.g., see accumulator signals for Row X=“0” and Row Y=“1” andfor Row X=“1” and Row Y=“1”), depending on the data value previouslystored in the dynamic latch.

After setting the secondary latch from the data values stored in thesense amplifier (and present on the data lines 205-1 (D) and 205-2 (D_),in the pseudo code above, “Deactivate LOAD” indicates that the LOADcontrol signal goes back low as shown at t₅ in FIG. 5 to cause theload/pass transistors 218-1 and 218-2 to stop conducting and therebyisolate the dynamic latch from the complementary data lines. However,the data value remains dynamically stored in secondary latch of theaccumulator.

After storing the data value on the secondary latch, the selected row(e.g., ROW X) is disabled (e.g., deselected, closed such as bydeactivating a select signal for a particular row) as indicated by“Close Row X” and indicated at t₆ in FIG. 5, which can be accomplishedby the access transistor turning off to decouple the selected cell fromthe corresponding data line. Once the selected row is closed and thememory cell is isolated from the data lines, the data lines can beprecharged as indicated by the “Precharge” in the pseudo code above. Aprecharge of the data lines can be accomplished by an equilibrateoperation, as indicated in FIG. 5 by the EQ signal going high at t₇. Asshown in each of the four sets of possible sense amplifier andaccumulator signals illustrated in FIG. 5 at t₇, the equilibrateoperation causes the voltage on data lines D and D_ to each return toV_(DD)/2. Equilibration can occur, for instance, prior to a memory cellsensing operation or the logical operations (described below).

A subsequent operation phase associated with performing the AND or theOR operation on the first data value (now stored in the sense amplifier206 and the secondary latch of the compute component 231) and the seconddata value (stored in a memory cell 202-1 coupled to Row Y 204-Y)includes performing particular steps which depend on the whether an ANDor an OR is to be performed. Examples of pseudo code associated with“ANDing” and “ORing” the data value residing in the accumulator (e.g.,the first data value stored in the memory cell 202-2 coupled to Row X204-X) and the second data value (e.g., the data value stored in thememory cell 202-1 coupled to Row Y 204-Y) are summarized below. Examplepseudo code associated with “ANDing” the data values can include:

Deactivate EQ Open Row Y Fire Sense Amps (after which Row Y data residesin the sense amps) Close Row Y      The result of the logic operation,in the next operation, will be placed on the sense amp, which willoverwrite any row that is active.      Even when Row Y is closed, thesense amplifier still contains the Row Y data value. Activate AND     This results in the sense amplifier being written to the value ofthe function (e.g., Row X AND Row Y)      If the accumulator contains a“0” (i.e., a voltage corresponding to a “0” on node S2 and a voltagecorresponding to a “1” on node S1), the sense amplifier data is writtento a “0”      If the accumulator contains a “1” (i.e., a voltagecorresponding to a “1” on node S2 and a voltage corresponding to a “0”on node S1), the sense amplifier data remains unchanged (Row Y data)     This operation leaves the data in the accumulator unchanged.Deactivate AND Precharge

In the pseudo code above, “Deactivate EQ” indicates that anequilibration signal corresponding to the sense amplifier 206 isdisabled (e.g., such that the complementary data lines 205-1 (D) and205-2 (D_) are no longer shorted to V_(DD)/2), which is illustrated inFIG. 5 at t₈. After equilibration is disabled, a selected row (e.g., ROWY) is enabled as indicated in the pseudo code above by “Open Row Y” andshown in FIG. 5 at t₉. When the voltage signal applied to ROW Y reachesthe threshold voltage (Vt) of the access transistor (e.g., 202-1)corresponding to the selected cell, the access transistor turns on andcouples the data line (e.g., D_ 205-1) to the selected cell (e.g., tocapacitor 203-1) which creates a differential voltage signal between thedata lines.

After Row Y is enabled, in the pseudo code above, “Fire Sense Amps”indicates that the sense amplifier 206 is enabled to amplify thedifferential signal between 205-1 (D) and 205-2 (D_), resulting in avoltage (e.g., V_(DD)) corresponding to a logic 1 or a voltage (e.g.,GND) corresponding to a logic 0 being on data line 205-1 (D) (and thevoltage corresponding to the other logic state being on complementarydata line 205-2 (D_)). As shown at t₁₀ in FIG. 5, the ACT positivecontrol signal (e.g., 265 shown in FIG. 2B) goes high and the RnIFnegative control signal (e.g., 228 shown in FIG. 2B) goes low to firethe sense amps. The sensed data value from memory cell 202-1 is storedin the primary latch of sense amplifier 206, as previously described.The secondary latch still corresponds to the data value from memory cell202-2 since the dynamic latch is unchanged.

After the second data value sensed from the memory cell 202-1 coupled toRow Y is stored in the primary latch of sense amplifier 206, in thepseudo code above, “Close Row Y” indicates that the selected row (e.g.,ROW Y) can be disabled if it is not desired to store the result of theAND logical operation back in the memory cell corresponding to Row Y.However, FIG. 5 shows that Row Y is left enabled such that the result ofthe logical operation can be stored back in the memory cellcorresponding to Row Y. Isolating the memory cell corresponding to Row Ycan be accomplished by the access transistor turning off to decouple theselected cell 202-1 from the data line 205-1 (D). After the selected RowY is configured (e.g., to isolate the memory cell or not isolate thememory cell), “Activate AND” in the pseudo code above indicates that theAND control signal goes high as shown in FIG. 5 at t₁₁, causing passtransistor 207-1 to conduct. In this manner, activating the AND controlsignal causes the value of the function (e.g., Row X AND Row Y) to bewritten to the sense amp.

With the first data value (e.g., Row X) stored in the dynamic latch ofthe accumulator 231 and the second data value (e.g., Row Y) stored inthe sense amplifier 206, if the dynamic latch of the compute component231 contains a “0” (i.e., a voltage corresponding to a “0” on node S2and a voltage corresponding to a “1” on node S1), the sense amplifierdata is written to a “0” (regardless of the data value previously storedin the sense amp) since the voltage corresponding to a “1” on node S1causes transistor 209-1 to conduct thereby coupling the sense amplifier206 to ground through transistor 209-1, pass transistor 207-1 and dataline 205-1 (D). When either data value of an AND operation is “0,” theresult is a “0.” Here, when the second data value (in the dynamic latch)is a “0,” the result of the AND operation is a “0” regardless of thestate of the first data value, and so the configuration of the sensingcircuitry causes the “0” result to be written and initially stored inthe sense amplifier 206. This operation leaves the data value in theaccumulator unchanged (e.g., from Row X).

If the secondary latch of the accumulator contains a “1” (e.g., from RowX), then the result of the AND operation depends on the data valuestored in the sense amplifier 206 (e.g., from Row Y). The result of theAND operation should be a “1” if the data value stored in the senseamplifier 206 (e.g., from Row Y) is also a “1,” but the result of theAND operation should be a “0” if the data value stored in the senseamplifier 206 (e.g., from Row Y) is also a “0.” The sensing circuitry250 is configured such that if the dynamic latch of the accumulatorcontains a “1” (i.e., a voltage corresponding to a “1” on node S2 and avoltage corresponding to a “0” on node S1), transistor 209-1 does notconduct, the sense amplifier is not coupled to ground (as describedabove), and the data value previously stored in the sense amplifier 206remains unchanged (e.g., Row Y data value so the AND operation result isa “1” if the Row Y data value is a “1” and the AND operation result is a“0” if the Row Y data value is a “0”). This operation leaves the datavalue in the accumulator unchanged (e.g., from Row X).

After the result of the AND operation is initially stored in the senseamplifier 206, “Deactivate AND” in the pseudo code above indicates thatthe AND control signal goes low as shown at t₁₂ in FIG. 5, causing passtransistor 207-1 to stop conducting to isolate the sense amplifier 206(and data line 205-1 (D)) from ground. If not previously done, Row Y canbe closed (as shown at t₁₃ in FIG. 5) and the sense amplifier can bedisabled (as shown at t₁₄ in FIG. 5 by the ACT positive control signalgoing low and the RnIF negative control signal goes high). With the datalines isolated, “Precharge” in the pseudo code above can cause aprecharge of the data lines by an equilibrate operation, as describedpreviously (e.g., commencing at t₁₄ shown in FIG. 5).

FIG. 5 shows, in the alternative, the behavior of voltage signals on thedata lines (e.g., 205-1 (D) and 205-2 (D_) shown in FIG. 2A) coupled tothe sense amplifier (e.g., 206 shown in FIG. 2A) and the behavior ofvoltage signals on nodes S1 and S1 of the secondary latch of the computecomponent (e.g., 231 shown in FIG. 2A) for an AND logical operationinvolving each of the possible combination of operands (e.g., Row X/RowY data values 00, 10, 01, and 11).

Although the timing diagrams illustrated in FIG. 5 and the pseudo codedescribed above indicate initiating the AND logical operation afterstarting to load the second operand (e.g., Row Y data value) into thesense amplifier, the circuit shown in FIG. 2A can be successfullyoperated by initiating the AND logical operation before starting to loadthe second operand (e.g., Row Y data value) into the sense amplifier.

FIG. 6 illustrates a timing diagram associated with performing a numberof logical operations using sensing circuitry in accordance with anumber of embodiments of the present disclosure. FIG. 6 illustrates atiming diagram associated with initiating an OR logical operation afterstarting to load the second operand (e.g., Row Y data value) into thesense amplifier. FIG. 6 illustrates the sense amplifier and accumulatorsignals for various combinations of first and second operand datavalues. The particular timing diagram signals are discussed below withrespect to the pseudo code associated with an AND logical operation ofthe circuit shown in FIG. 2A.

A subsequent operation phase can alternately be associated withperforming the OR operation on the first data value (now stored in thesense amplifier 206 and the secondary latch of the compute component231) and the second data value (stored in a memory cell 202-1 coupled toRow Y 204-Y). The operations to load the Row X data into the senseamplifier and accumulator that were previously described with respect totimes t₁-t₇ shown in FIG. 5 are not repeated with respect to FIG. 6.Example pseudo code associated with “ORing” the data values can include:

Deactivate EQ Open Row Y Fire Sense Amps (after which Row Y data residesin the sense amps) Close Row Y    When Row Y is closed, the senseamplifier still contains the Row Y    data value. Activate OR

-   -   This results in the sense amplifier being written to the value        of the function (e.g., Row X OR Row Y), which may overwrite the        data value from Row Y previously stored in the sense amplifier        as follows:

  If the accumulator contains a “0” (i.e., a voltage corresponding to a“0” on node S2 and a voltage corresponding to a “1” on node S1), thesense amplifier data remains unchanged (Row Y data)   If the accumulatorcontains a “1” (i.e., a voltage corresponding to a “1” on node S2 and avoltage corresponding to a “0” on node S1), the sense amplifier data iswritten to a “1”   This operation leaves the data in the accumulatorunchanged. Deactivate OR Precharge

The “Deactivate EQ” (shown at t₈ in FIG. 6), “Open Row Y” (shown at t₉in FIG. 6), “Fire Sense Amps” (shown at t₁₀ in FIG. 6), and “Close RowY” (shown at t₁₃ in FIG. 6, and which may occur prior to initiating theparticular logical function control signal), shown in the pseudo codeabove indicate the same functionality as previously described withrespect to the AND operation pseudo code. Once the configuration ofselected Row Y is appropriately configured (e.g., enabled if logicaloperation result is to be stored in memory cell corresponding to Row Yor closed to isolate memory cell if result if logical operation resultis not to be stored in memory cell corresponding to Row Y), “ActivateOR” in the pseudo code above indicates that the OR control signal goeshigh as shown at t₁₁ in FIG. 6, which causes pass transistor 207-2 toconduct. In this manner, activating the OR control signal causes thevalue of the function (e.g., Row X OR Row Y) to be written to the senseamp.

With the first data value (e.g., Row X) stored in the secondary latch ofthe compute component 231 and the second data value (e.g., Row Y) storedin the sense amplifier 206, if the dynamic latch of the accumulatorcontains a “0” (i.e., a voltage corresponding to a “0” on node S2 and avoltage corresponding to a “1” on node S1), then the result of the ORoperation depends on the data value stored in the sense amplifier 206(e.g., from Row Y). The result of the OR operation should be a “1” ifthe data value stored in the sense amplifier 206 (e.g., from Row Y) is a“1,” but the result of the OR operation should be a “0” if the datavalue stored in the sense amplifier 206 (e.g., from Row Y) is also a“0.” The sensing circuitry 250 is configured such that if the dynamiclatch of the accumulator contains a “0,” with the voltage correspondingto a “0” on node S2, transistor 209-2 is off and does not conduct (andpass transistor 207-1 is also off since the AND control signal is notasserted) so the sense amplifier 206 is not coupled to ground (eitherside), and the data value previously stored in the sense amplifier 206remains unchanged (e.g., Row Y data value such that the OR operationresult is a “1” if the Row Y data value is a “1” and the OR operationresult is a “0” if the Row Y data value is a “0”).

If the dynamic latch of the accumulator contains a “1” (i.e., a voltagecorresponding to a “1” on node S2 and a voltage corresponding to a “0”on node S1), transistor 209-2 does conduct (as does pass transistor207-2 since the OR control signal is asserted), and the sense amplifier206 input coupled to data line 205-2 (D_) is coupled to ground since thevoltage corresponding to a “1” on node S2 causes transistor 209-2 toconduct along with pass transistor 207-2 (which also conducts since theOR control signal is asserted). In this manner, a “1” is initiallystored in the sense amplifier 206 as a result of the OR operation whenthe secondary latch of the accumulator contains a “1” regardless of thedata value previously stored in the sense amp. This operation leaves thedata in the accumulator unchanged. FIG. 6 shows, in the alternative, thebehavior of voltage signals on the data lines (e.g., 205-1 (D) and 205-2(D_) shown in FIG. 2A) coupled to the sense amplifier (e.g., 206 shownin FIG. 2A) and the behavior of voltage signals on nodes S1 and S2 ofthe secondary latch of the compute component 231 for an OR logicaloperation involving each of the possible combination of operands (e.g.,Row X/Row Y data values 00, 10, 01, and 11).

After the result of the OR operation is initially stored in the senseamplifier 206, “Deactivate OR” in the pseudo code above indicates thatthe OR control signal goes low as shown at t₁₂ in FIG. 6, causing passtransistor 207-2 to stop conducting to isolate the sense amplifier 206(and data line D 205-2) from ground. If not previously done, Row Y canbe closed (as shown at t₁₃ in FIG. 6) and the sense amplifier can bedisabled (as shown at t₁₄ in FIG. 6 by the ACT positive control signalgoing low and the RnIF negative control signal going high). With thedata lines isolated, “Precharge” in the pseudo code above can cause aprecharge of the data lines by an equilibrate operation, as describedpreviously and shown at t₁₄ in FIG. 6.

The sensing circuitry 250 illustrated in FIG. 2A can provide additionallogical operations flexibility as follows. By substituting operation ofthe ANDinv control signal for operation of the AND control signal,and/or substituting operation of the ORinv control signal for operationof the OR control signal in the AND and OR operations described above,the logical operations can be changed from {Row X AND Row Y} to {˜Row XAND Row Y}(where “˜Row X” indicates an opposite of the Row X data value,e.g., NOT Row X) and can be changed from {Row X OR Row Y} to {˜Row X ORRow Y}. For example, during an AND operation involving the inverted datavalues, the ANDinv control signal can be asserted instead of the ANDcontrol signal, and during an OR operation involving the inverted datavalues, the ORInv control signal can be asserted instead of the ORcontrol signal. Activating the ORinv control signal causes transistor214-1 to conduct and activating the ANDinv control signal causestransistor 214-2 to conduct. In each case, asserting the appropriateinverted control signal can flip the sense amplifier and cause theresult initially stored in the sense amplifier 206 to be that of the ANDoperation using inverted Row X and true Row Y data values or that of theOR operation using the inverted Row X and true Row Y data values. A trueor compliment version of one data value can be used in the accumulatorto perform the logical operation (e.g., AND, OR), for example, byloading a data value to be inverted first and a data value that is notto be inverted second.

In a similar approach to that described above with respect to invertingthe data values for the AND and OR operations described above, thesensing circuitry shown in FIG. 2A can perform a NOT (e.g., invert)operation by putting the non-inverted data value into the dynamic latchof the accumulator and using that data to invert the data value in thesense amplifier 206. As previously mentioned, activating the ORinvcontrol signal causes transistor 214-1 to conduct and activating theANDinv control signal causes transistor 214-2 to conduct. The ORinvand/or ANDinv control signals are used in implementing the NOT function,as described further below:

Copy Row X into the Accumulator   Deactivate EQ   Open Row X   FireSense Amps (after which Row X data resides in the sense amps)   ActivateLOAD (sense amplifier data (Row X) is transferred to nodes S1 and S2 ofthe Accumulator and resides there dynamically   Deactivate LOAD  Activate ANDinv and ORinv (which puts the compliment data value on thedata lines)      This results in the data value in the sense amplifierbeing   inverted (e.g., the sense amplifier latch is flipped)      Thisoperation leaves the data in the accumulator unchanged   DeactivateANDinv and ORinv   Close Row X Precharge

The “Deactivate EQ,” “Open Row X,” “Fire Sense Amps,” “Activate LOAD,”and “Deactivate LOAD” shown in the pseudo code above indicate the samefunctionality as the same operations in the pseudo code for the “CopyRow X into the Accumulator” initial operation phase described aboveprior to pseudo code for the AND operation and OR operation. However,rather than closing the Row X and Precharging after the Row X data isloaded into the sense amplifier 206 and copied into the dynamic latch, acompliment version of the data value in the dynamic latch of theaccumulator can be placed on the data line and thus transferred to thesense amplifier 206 by enabling (e.g., causing transistor to conduct)and disabling the invert transistors (e.g., ANDinv and ORinv). Thisresults in the sense amplifier 206 being flipped from the true datavalue that was previously stored in the sense amplifier to a complimentdata value (e.g., inverted data value) stored in the sense amp. That is,a true or compliment version of the data value in the accumulator can betransferred to the sense amplifier by activating and deactivating ANDinvand ORinv. This operation leaves the data in the accumulator unchanged.

Because the sensing circuitry 250 shown in FIG. 2A initially stores theresult of the AND, OR, and NOT logical operations in the sense amplifier206 (e.g., on the sense amplifier nodes), these logical operationresults can be communicated easily and quickly to any enabled row, anyrow activated after the logical operation is complete, and/or into thesecondary latch of the compute component 231. The sense amplifier 206and sequencing for the AND, OR, and/or NOT logical operations can alsobe interchanged by appropriate firing of the AND, OR, ANDinv, and/orORinv control signals (and operation of corresponding transistors havinga gate coupled to the particular control signal) before the senseamplifier 206 fires.

When performing logical operations in this manner, the sense amplifier206 can be pre-seeded with a data value from the dynamic latch of theaccumulator to reduce overall current utilized because the sense amps206 are not at full rail voltages (e.g., supply voltage orground/reference voltage) when accumulator function is copied to thesense amplifier 206. An operation sequence with a pre-seeded senseamplifier 206 either forces one of the data lines to the referencevoltage (leaving the complementary data line at V_(DD)/2, or leaves thecomplementary data lines unchanged. The sense amplifier 206 pulls therespective data lines to full rails when the sense amplifier 206 fires.Using this sequence of operations will overwrite data in an enabled row.

A SHIFT operation can be accomplished by multiplexing (“muxing”) twoneighboring data line complementary pairs using a traditional DRAMisolation (ISO) scheme. According to embodiments of the presentdisclosure, the shift circuitry 223 can be used for shifting data valuesstored in memory cells coupled to a particular pair of complementarydata lines to the sensing circuitry 250 (e.g., sense amplifier 206)corresponding to a different pair of complementary data lines (e.g.,such as a sense amplifier 206 corresponding to a left or right adjacentpair of complementary data lines. As used herein, a sense amplifier 206corresponds to the pair of complementary data lines to which the senseamplifier is coupled when isolation transistors 221-1 and 221-2 areconducting. The SHIFT operations (right or left) do not pre-copy the RowX data value into the accumulator. Operations to shift right Row X canbe summarized as follows:

Deactivate Norm and Activate Shift Deactivate EQ Open Row X Fire SenseAmps (after which shifted Row X data resides in the sense amps) ActivateNorm and Deactivate Shift Close Row X Precharge

In the pseudo code above, “Deactivate Norm and Activate Shift” indicatesthat a NORM control signal goes low causing isolation transistors 221-1and 221-2 of the shift circuitry 223 to not conduct (e.g., isolate thesense amplifier from the corresponding pair of complementary datalines). The SHIFT control signal goes high causing isolation transistors221-3 and 221-4 to conduct, thereby coupling the sense amplifier 206 tothe left adjacent pair of complementary data lines (e.g., on the memoryarray side of non-conducting isolation transistors 221-1 and 221-2 forthe left adjacent pair of complementary data lines).

After the shift circuitry 223 is configured, the “Deactivate EQ,” “OpenRow X,” and “Fire Sense Amps” shown in the pseudo code above indicatethe same functionality as the same operations in the pseudo code for the“Copy Row X into the Accumulator” initial operation phase describedabove prior to pseudo code for the AND operation and OR operation. Afterthese operations, the Row X data value for the memory cell coupled tothe left adjacent pair of complementary data lines is shifted right andstored in the sense amplifier 206.

In the pseudo code above, “Activate Norm and Deactivate Shift” indicatesthat a NORM control signal goes high causing isolation transistors 221-1and 221-2 of the shift circuitry 223 to conduct (e.g., coupling thesense amplifier to the corresponding pair of complementary data lines),and the SHIFT control signal goes low causing isolation transistors221-3 and 221-4 to not conduct and isolating the sense amplifier 206from the left adjacent pair of complementary data lines (e.g., on thememory array side of non-conducting isolation transistors 221-1 and221-2 for the left adjacent pair of complementary data lines). Since RowX is still active, the Row X data value that has been shifted right istransferred to Row X of the corresponding pair of complementary datalines through isolation transistors 221-1 and 221-2.

After the Row X data values are shifted right to the corresponding pairof complementary data lines, the selected row (e.g., ROW X) is disabledas indicated by “Close Row X” in the pseudo code above, which can beaccomplished by the access transistor turning off to decouple theselected cell from the corresponding data line. Once the selected row isclosed and the memory cell is isolated from the data lines, the datalines can be precharged as indicated by the “Precharge” in the pseudocode above. A precharge of the data lines can be accomplished by anequilibrate operation, as described above. Operations to shift left RowX can be summarized as follows:

Activate Norm and Deactivate Shift Deactivate EQ Open Row X Fire SenseAmps (after which Row X data resides in the sense amps) Deactivate Normand Activate Shift   Sense amplifier data (shifted left Row X) istransferred to Row X Close Row X Precharge

In the pseudo code above, “Activate Norm and Deactivate Shift” indicatesthat a NORM control signal goes high causing isolation transistors 221-1and 221-2 of the shift circuitry 223 to conduct, and the SHIFT controlsignal goes low causing isolation transistors 221-3 and 221-4 to notconduct. This configuration couples the sense amplifier 206 to acorresponding pair of complementary data lines and isolates the senseamplifier from the right adjacent pair of complementary data lines.

After the shift circuitry is configured, the “Deactivate EQ,” “Open RowX,” and “Fire Sense Amps” shown in the pseudo code above indicate thesame functionality as the same operations in the pseudo code for the“Copy Row X into the Accumulator” initial operation phase describedabove prior to pseudo code for the AND operation and OR operation. Afterthese operations, the Row X data value for the memory cell coupled tothe pair of complementary data lines corresponding to the sensecircuitry 250 is stored in the sense amplifier 206.

In the pseudo code above, “Deactivate Norm and Activate Shift” indicatesthat a NORM control signal goes low causing isolation transistors 221-1and 221-2 of the shift circuitry 223 to not conduct (e.g., isolate thesense amplifier from the corresponding pair of complementary datalines), and the SHIFT control signal goes high causing isolationtransistors 221-3 and 221-4 to conduct coupling the sense amplifier tothe left adjacent pair of complementary data lines (e.g., on the memoryarray side of non-conducting isolation transistors 221-1 and 221-2 forthe left adjacent pair of complementary data lines. Since Row X is stillactive, the Row X data value that has been shifted left is transferredto Row X of the left adjacent pair of complementary data lines.

After the Row X data values are shifted left to the left adjacent pairof complementary data lines, the selected row (e.g., ROW X) is disabledas indicated by “Close Row X,” which can be accomplished by the accesstransistor turning off to decouple the selected cell from thecorresponding data line. Once the selected row is closed and the memorycell is isolated from the data lines, the data lines can be prechargedas indicated by the “Precharge” in the pseudo code above. A precharge ofthe data lines can be accomplished by an equilibrate operation, asdescribed above.

According to various embodiments, general computing can be enabled in amemory array core of a processor-in-memory (PIM) device such as a DRAMone transistor per memory cell (e.g., 1T1C) configuration at 6F^2 or4F^2 memory cell sizes, for example. The advantage of the apparatusesand methods described herein is not realized in terms of singleinstruction speed, but rather the cumulative speed that can be achievedby an entire bank of data being computed in parallel without evertransferring data out of the memory array (e.g., DRAM) or firing acolumn decode. In other words, data transfer time can be eliminated. Forexample, apparatus of the present disclosure can perform ANDs or ORssimultaneously using data values in memory cells coupled to a data line(e.g., a column of 16K memory cells).

In previous approach sensing circuits where data is moved out forlogical operation processing (e.g., using 32 or 64 bit registers), feweroperations can be performed in parallel compared to the apparatus of thepresent disclosure. In this manner, significantly higher throughput iseffectively provided in contrast to conventional configurationsinvolving a central processing unit (CPU) discrete from the memory suchthat data must be transferred therebetween. An apparatus and/or methodsaccording to the present disclosure can also use less energy/area thanconfigurations where the CPU is discrete from the memory. Furthermore,an apparatus and/or methods of the present disclosure can improve uponthe smaller energy/area advantages since the in-memory-array logicaloperations save energy by eliminating certain data value transfers.

FIG. 7 illustrates a timing diagram associated with performing a numberof logical operations using sensing circuitry in accordance with anumber of embodiments of the present disclosure. The functionality ofthe sensing circuitry 250 of FIG. 2A is described below with respect toperforming logical operations and initially storing a result in thecompute component 231 (e.g., secondary latch of the accumulator). Thetiming diagram shown in FIG. 7 illustrates signals (e.g., voltagesignals) associated with performing a first operation phase of a logicaloperation (e.g., an R-input logical operation) using the sensingcircuitry illustrated in FIG. 2A. The first operation phase describedwith respect to FIG. 7 can be a first operation phase of an AND, NAND,OR, or NOR operation, for instance. Performing the operation phaseillustrated in FIG. 7 can involve consuming significantly less energy(e.g., about half) than previous processing approaches that may involveproviding a full swing between voltage rails (e.g., between a supply andground).

In the example illustrated in FIG. 7, the voltage rails corresponding tocomplementary logic values (e.g., “1” and “0”) are a supply voltage(V_(DD)) and a reference voltage (e.g., ground (Gnd)). Prior toperforming a logical operation, an equilibration can occur such that thecomplementary data lines D and D_ are shorted together at anequilibration voltage (V_(DD)/2), as previously described.

The first operation phase of a logical operation described belowinvolves loading a first operand of the logical operation into theaccumulator. The time references (e.g., t₁, etc.) shown in FIG. 7 do notnecessarily represent a same absolute or relative time as similar timereferences in other timing diagrams.

t time t₁, the equilibration signal 726 is deactivated, and then aselected row is enabled (e.g., the row corresponding to a memory cellwhose data value is to be sensed and used as a first input). Signal704-0 represents the voltage signal applied to the selected row (e.g.,Row Y 204-Y shown in FIG. 2A). When row signal 704-0 reaches thethreshold voltage (Vt) of the access transistor (e.g., 202-1 shown inFIG. 2A) corresponding to the selected cell, the access transistor turnson and couples the data line D to the selected memory cell (e.g., to thecapacitor 203-1 shown in FIG. 2A if the cell is a 1T1C DRAM cell), whichcreates a differential voltage signal between the data lines D and D_(e.g., as indicated by signals 705-1 and 705-2 on the data lines,respectively) between times t₂ and t₃. The voltage of the selected cellis represented by signal 703. Due to conservation of energy, creatingthe differential signal between data lines D and D_ (e.g., by couplingthe cell to data line D) does not consume energy, since the energyassociated with enabling/disabling the row signal 704-0 can be amortizedover the plurality of memory cells coupled to the row.

At time t₃, the sense amplifier (e.g., 206 shown in FIG. 2A) isactivated (e.g., a positive control signal 765 (e.g., corresponding toACT 265 shown in FIG. 2B) goes high and the negative control signal 728(e.g., corresponding to RnIF 228 shown in FIG. 2B) goes low), whichamplifies the differential signal between data lines D and D_, resultingin a voltage (e.g., V_(DD)) corresponding to a logic “1” or a voltage(e.g., ground) corresponding to a logic “0” being on data line D (andthe other voltage being on complementary data line D_), such that thesensed data value is stored in the primary latch of sense amplifier 206.The primary energy consumption occurs in charging the data line D(205-1) from the equilibration voltage V_(DD)/2 to the rail voltageV_(DD). FIG. 7 shows, in example, the data line voltages 705-1 and 705-2that correspond to a logic “1” being on data line D.

According to some embodiments, the primary latch of sense amplifier 206can be coupled to the complementary data lines D and D_ throughrespective pass transistors (not shown in FIG. 2B but in a similarconfiguration as the manner in which latch 264 is coupled to the datalines D and D_ through load/pass transistors 218-1 and 218-2 shown inFIG. 2A). The Passd control signal 711 controls one pass transistor. ThePassdb control signal controls the other pass transistor, and here thePassdb control signal can behave here the same as the Passd controlsignal.

At time t₄, the pass transistors (if present) can be enabled (e.g., viarespective Passd and Passdb control signals 711 applied to control linescoupled to the respective gates of the pass transistors going high). Attime t₅, the accumulator positive control signal 712-1 (e.g., Accumb)and the accumulator positive control signal 712-2 (e.g., Accum) areactivated via respective control lines 212-1 and 212-2 shown in FIG. 2A.As described below, the accumulator control signals ACCUMB 712-1 andACCUM 712-2 may remain activated for subsequent operation phases. Assuch, in this example, activating the control signals ACCUMB 712-1 andACCUM 712-2 enables the secondary latch (e.g., accumulator) of computecomponent 231-6 shown in FIG. 2A. The sensed data value stored in senseamplifier 206 is transferred (e.g., copied) to the secondary latch,including the dynamic latch and latch 264.

At time t₆, the Passd control signal 711 (and the Passdb control signal)goes low thereby turning off the pass transistors (if present). However,since the accumulator control signals ACCUMB 712-1 and ACCUM 712-2remain activated, an accumulated result is stored (e.g., latched) in thesecondary latches (e.g., accumulator). At time t₇, the row signal 704-0is deactivated, and the array sense amps are disabled at time t₈ (e.g.,sense amplifier control signals 728 and 765 are deactivated).

At time t₉, the data lines D and D_ are equilibrated (e.g.,equilibration signal 726 is activated), as illustrated by data linevoltage signals 705-1 and 705-2 moving from their respective rail valuesto the equilibration voltage (V_(DD)/2). The equilibration consumeslittle energy due to the law of conservation of energy. As describedbelow in association with FIG. 2B, equilibration can involve shortingthe complementary data lines D and D_ together at an equilibrationvoltage, which is V_(DD)/2, in this example. Equilibration can occur,for instance, prior to a memory cell sensing operation.

FIGS. 8 and 9 respectively illustrate timing diagrams associated withperforming a number of logical operations using sensing circuitry inaccordance with a number of embodiments of the present disclosure.Timing diagrams shown in FIGS. 8 and 9 illustrate signals (e.g., voltagesignals) associated with performing a number of intermediate operationphases of a logical operation (e.g., an R-input logical operation). Forinstance, timing diagram shown in FIG. 8 corresponds to a number ofintermediate operation phases of an R-input NAND operation or an R-inputAND operation, and timing diagram shown in FIG. 9 corresponds to anumber of intermediate operation phases of an R-input NOR operation oran R-input OR operation. For example, performing an AND or NANDoperation can include performing the operation phase shown in FIG. 8 oneor more times subsequent to an initial operation phase such as thatdescribed with respect to FIG. 7. Similarly, performing an OR or NORoperation can include performing the operation phase shown and describedwith respect to FIG. 9 one or more times subsequent to an initialoperation phase such as that described with respect to FIG. 7.

As shown in the timing diagrams illustrated in FIGS. 8 and 9, at timet₁, equilibration is disabled (e.g., the equilibration signal 826/926 isdeactivated), and then a selected row is enabled (e.g., the rowcorresponding to a memory cell whose data value is to be sensed and usedas an input such as a second input, third input, etc.). Signal804-1/904-1 represents the voltage signal applied to the selected row(e.g., Row Y 204-Y shown in FIG. 2A). When row signal 804-1 reaches thethreshold voltage (Vt) of the access transistor (e.g., 202-1 shown inFIG. 2A) corresponding to the selected cell, the access transistor turnson and couples the data line D to the selected memory cell (e.g., to thecapacitor 203-1 if the cell is a 1T1C DRAM cell), which creates adifferential voltage signal between the data lines D and D_ (e.g., asindicated by signals 805-1/905-1 and 805-2/905-2, respectively) betweentimes t₂ and t₃. The voltage of the selected cell is represented bysignal 803/903. Due to conservation of energy, creating the differentialsignal between D and D_ (e.g., by coupling the cell to data line D) doesnot consume energy, since the energy associated withactivating/deactivating the row signal 804-1/904-1 can be amortized overthe plurality of memory cells coupled to the row.

At time t₃, the sense amplifier (e.g., 206 shown in FIG. 2A) is enabled(e.g., a positive control signal 865/965 (e.g., corresponding to ACT 233shown in FIG. 2B) goes high, and the negative control signal 828/928(e.g., RnIF 228 shown in FIG. 2B) goes low), which amplifies thedifferential signal between D and D_, resulting in a voltage (e.g.,V_(DD)) corresponding to a logic 1 or a voltage (e.g., ground)corresponding to a logic 0 being on data line D (and the other voltagebeing on complementary data line D_), such that the sensed data value isstored in the primary latch of sense amplifier 206. The primary energyconsumption occurs in charging the data line D (205-1) from theequilibration voltage V_(DD)/2 to the rail voltage V_(DD).

As shown in timing diagrams illustrated in FIGS. 8 and 9, at time t₄(e.g., after the selected cell is sensed), only one of control signals811-1 (Passd) shown in FIG. 8 and 911-2 (Passdb) shown in FIG. 9 isactivated (e.g., only one of pass transistors (if present) is enabled),depending on the particular logic operation. For example, since thetiming diagram illustrated in FIG. 8 corresponds to an intermediatephase of a NAND or AND operation, control signal 811-1 (Passd) isactivated at time t4 to turn on the pass transistor coupling the primarylatch to data line D and the Passdb control signal remains deactivatedleaving the pass transistor coupling the primary latch to data line D_turned off. Conversely, since the timing diagram illustrated in FIG. 9corresponds to an intermediate phase of a NOR or OR operation, controlsignal 911-2 (Passdb) is activated at time t4 to turn on the passtransistor coupling the primary latch to data line D_ and control signalPassd remains deactivated leaving the pass transistor coupling theprimary latch to data line D turned off. Recall from above that theaccumulator control signals 712-1 (Accumb) and 712-2 (Accum) wereactivated during the initial operation phase described with respect toFIG. 7, and they remain activated during the intermediate operationphase(s).

Since the accumulator was previously enabled, activating only Passd(811-1 as shown in FIG. 8) results in accumulating the data valuecorresponding to the voltage signal 805-1 shown in FIG. 8 correspondingto data line D. Similarly, activating only Passdb (911-2 as shown inFIG. 9) results in accumulating the data value corresponding to thevoltage signal 905-2 corresponding to data line D_. For instance, in anexample AND/NAND operation shown in the timing diagram illustrated inFIG. 8 in which only Passd (811-1) is activated, if the data valuestored in the second selected memory cell is a logic “0,” then theaccumulated value associated with the secondary latch is asserted lowsuch that the secondary latch stores logic “0.” If the data value storedin the second selected memory cell is not a logic “0,” then thesecondary latch retains its stored first selected memory cell data value(e.g., a logic “1” or a logic “0”). As such, in this AND/NAND operationexample, the secondary latch is serving as a zeroes (0s) accumulator.

Similarly, in an example OR/NOR operation shown in the timing diagramillustrated in FIG. 9 in which only Passdb 911-2 is activated, if thedata value stored in the second selected memory cell is a logic “1,”then the accumulated value associated with the secondary latch isasserted high such that the secondary latch stores logic “1.” If thedata value stored in the second selected memory cell is not a logic “1,”then the secondary latch retains its stored first selected memory celldata value (e.g., a logic “1” or a logic “0”). As such, in this OR/NORoperation example, the secondary latch is effectively serving as a ones(1s) accumulator since voltage signal 905-2 on D_ is setting the truedata value of the accumulator.

At the conclusion of an intermediate operation phase such as that shownin FIG. 8 or 9, the Passd signal 811-1 (e.g., for AND/NAND) or thePassdb signal 911-2 (e.g., for OR/NOR) is deactivated (e.g., at timet5), the selected row is disabled (e.g., at time t6), the senseamplifier is disabled (e.g., at time t7), and equilibration occurs(e.g., at time t8). An intermediate operation phase such as thatillustrated in FIG. 8 or 9 can be repeated in order to accumulateresults from a number of additional rows. As an example, the sequence oftiming diagram illustrated in FIGS. 8 and/or 9 can be performed asubsequent (e.g., second) time for a third memory cell, a subsequent(e.g., third) time for a fourth memory cell, etc. For instance, for a10-input NOR operation, the intermediate phase shown in FIG. 9 can occur9 times to provide 9 inputs of the 10-input logical operation, with thetenth input being determined during the initial operation phase (e.g.,as described with respect to FIG. 7).

FIG. 10 illustrates a timing diagram associated with performing a numberof logical operations using sensing circuitry in accordance with anumber of embodiments of the present disclosure. The timing diagramillustrated in FIG. 10 shows signals (e.g., voltage signals) associatedwith performing a last operation phase of a logical operation (e.g., anR-input logical operation). For instance, the timing diagram illustratedin FIG. 10 corresponds to a last operation phase of an R-input ANDoperation or an R-input OR operation.

For example, performing a last operation phase of an R-input can includeperforming the operation phase shown in FIG. 10 subsequent to a numberof iterations of the intermediate operation phase(s) described inassociation with FIGS. 8 and/or 9. Table 2 shown below indicates theFigures corresponding to the sequence of operation phases associatedwith performing a number of R-input logical operations in accordancewith a number of embodiments described herein.

TABLE 2 Operation FIG. 7 FIG. 8 FIG. 9 FIG. 10 AND First phase R-1 Lastphase iterations NAND First phase R-1 iterations OR First phase R-1 Lastphase iterations NOR First phase R-1 iterations

A NAND operation can be implemented, for example, by storing the resultof the R−1 iterations for an AND operation in the sense amplifier, theninverting the sense amplifier before conducting the last operation phaseto store the result (described below). A NOR operation can beimplemented, for example, by storing the result of the R−1 iterationsfor an OR operation in the sense amplifier, then inverting the senseamplifier before conducting the last operation phase to store the result(described below).

The last operation phase illustrated in the timing diagram of FIG. 10 isdescribed in association with storing a result of an R-input logicaloperation to a row of the array (e.g., array 230 shown in FIG. 2A).However, as described above, in a number of embodiments, the result canbe stored to a suitable location other than back to the array (e.g., toan external register associated with a controller and/or host processor,to a memory array of a different memory device, etc., via I/O lines).

As shown in timing diagram illustrated in FIG. 10, at time t₁,equilibration is disabled (e.g., the equilibration signal 1026 isdeactivated) such that data lines D and D_ are floating. At time t2, thePassd control signal 1011 (and Passdb signal) is activated for an AND orOR operation.

Activating the Passd control signal 1011 (and Passdb signal) (e.g., inassociation with an AND or OR operation) transfers the accumulatedoutput stored in the secondary latch of compute component 231-6 shown inFIG. 2A to the primary latch of sense amplifier 206. For instance, foran AND operation, if any of the memory cells sensed in the prioroperation phases (e.g., the first operation phase illustrated in FIG. 7and one or more iterations of the intermediate operation phaseillustrated in FIG. 8) stored a logic “0” (e.g., if any of the R-inputsof the AND operation were a logic “0”), then the data line D_ will carrya voltage corresponding to logic “1” (e.g., V_(DD)) and data line D willcarry a voltage corresponding to logic “0” (e.g., ground). For this ANDoperation example, if all of the memory cells sensed in the prioroperation phases stored a logic “1” (e.g., all of the R-inputs of theAND operation were logic “1”), then the data line D_ will carry avoltage corresponding to logic “0” and data line D will carry a voltagecorresponding to logic “1”. At time t3, the primary latch of senseamplifier 206 is then enabled (e.g., a positive control signal 1065(e.g., corresponding to ACT 265 shown in FIG. 2B) goes high and thenegative control signal 1028 (e.g., corresponding to RnIF 228 shown inFIG. 2B) goes low), which amplifies the differential signal between datalines D and D such that the data line D now carries the ANDed result ofthe respective input data values as determined from the memory cellssensed during the prior operation phases. As such, data line D will beat ground if any of the input data values are a logic “0” and data lineD will be at V_(DD) if all of the input data values are a logic “1.”

For an OR operation, if any of the memory cells sensed in the prioroperation phases (e.g., the first operation phase of FIG. 7 and one ormore iterations of the intermediate operation phase shown in FIG. 9)stored a logic “1” (e.g., if any of the R-inputs of the OR operationwere a logic “1”), then the data line D_ will carry a voltagecorresponding to logic “0” (e.g., ground) and data line D will carry avoltage corresponding to logic “1” (e.g., V_(DD)). For this OR example,if all of the memory cells sensed in the prior operation phases stored alogic “0” (e.g., all of the R-inputs of the OR operation were logic“0”), then the data line D will carry a voltage corresponding to logic“0” and data line D_ will carry a voltage corresponding to logic “1.” Attime t3, the primary latch of sense amplifier 206 is then enabled andthe data line D now carries the ORed result of the respective input datavalues as determined from the memory cells sensed during the prioroperation phases. As such, data line D will be at V_(DD) if any of theinput data values are a logic “1” and data line D will be at ground ifall of the input data values are a logic “0.”

The result of the R-input AND or OR logical operations can then bestored back to a memory cell of array 230 shown in FIG. 2A. In theexamples shown in FIG. 10, the result of the R-input logical operationis stored to a memory cell coupled to the last row enabled (e.g., row ofthe last logical operation operand). Storing the result of the logicaloperation to a memory cell simply involves enabling the associated rowaccess transistor by enabling the particular row. The capacitor of thememory cell will be driven to a voltage corresponding to the data valueon the data line D (e.g., logic “1” or logic “0”), which essentiallyoverwrites whatever data value was previously stored in the selectedmemory cell. It is noted that the selected memory cell can be a samememory cell that stored a data value used as an input for the logicaloperation. For instance, the result of the logical operation can bestored back to a memory cell that stored an operand of the logicaloperation.

The timing diagram illustrated in FIG. 10 show, at time t3, the positivecontrol signal 1065 and the negative control signal 1028 beingdeactivated (e.g., signal 1065 goes high and signal 1028 goes low) todisable the sense amplifier 206 shown in FIG. 2A. At time t4 the Passdcontrol signal 1011 (and Passdb signal) that was activated at time t2 isdeactivated. Embodiments are not limited to this example. For instance,in a number of embodiments, the sense amplifier 206 shown in FIG. 2A maybe enabled subsequent to time t4 (e.g., after the Passd control signal1011 (and Passdb signal) are deactivated).

As shown in FIG. 10, at time t5, a selected row is enabled (e.g., by rowactivation signal 1004 going high, which drives the capacitor of theselected cell to the voltage corresponding to the logic value stored inthe accumulator. At time t6 the selected row is disabled. At time t7 thesense amplifier 206 shown in FIG. 2A is disabled (e.g., positive controlsignal 1028 and negative control signal 1065 are deactivated), and attime t8 equilibration occurs (e.g., signal 1026 is activated and thevoltages on the complementary data lines 1005-1 (D) and 1005-2 (D_) arebrought to the equilibration voltage).

Although the example of performing a last operation phase of an R-inputwas discussed above with respect to FIG. 10 for performing AND and ORlogical operations, embodiments are not limited to these logicaloperations. For example, the NAND and NOR operations can also involve alast operation phase of an R-input that is stored back to a memory cellof array 230 using control signals to operate the sensing circuitryillustrated in FIG. 2A.

FIG. 11 is a schematic diagram illustrating sensing circuitry havingselectable logical operation selection logic in accordance with a numberof embodiments of the present disclosure. FIG. 11 shows a senseamplifier 1106 coupled to a pair of complementary sense lines 1105-1 and1105-2, and a compute component 1131 coupled to the sense amplifier 1106via pass gates 1107-1 and 1107-2. The gates of the pass gates 1107-1 and1107-2 can be controlled by a logical operation selection logic signal,PASS, which can be output from logical operation selection logic 1113-5.FIG. 11 shows the compute component 1131 labeled “A” and the senseamplifier 1106 labeled “B” to indicate that the data value stored in thecompute component 1131 is the “A” data value and the data value storedin the sense amplifier 1106 is the “B” data value shown in the logictables illustrated with respect to FIG. 12.

The sensing circuitry 1150 illustrated in FIG. 11 includes logicaloperation selection logic 1113-5. In this example, the logic 1113-5comprises swap gates 1142 controlled by a logical operation selectionlogic signal PASS*. The logical operation selection logic 1113-5 alsocomprises four logic selection transistors: logic selection transistor1162 coupled between the gates of the swap transistors 1142 and a TFsignal control line, logic selection transistor 1152 coupled between thegates of the pass gates 1107-1 and 1107-2 and a TT signal control line,logic selection transistor 1154 coupled between the gates of the passgates 1107-1 and 1107-2 and a FT signal control line, and logicselection transistor 1164 coupled between the gates of the swaptransistors 1142 and a FF signal control line. Gates of logic selectiontransistors 1162 and 1152 are coupled to the true sense line (e.g.,1105-1) through isolation transistor 1181-1 (having a gate coupled to anISO signal control line), and gates of logic selection transistors 1164and 1154 are coupled to the complementary sense line (e.g., 1105-2)through isolation transistor 1181-2 (also having a gate coupled to anISO signal control line).

Logic selection transistors 1152 and 1154 are arranged similarly totransistor 207-1 (coupled to an AND signal control line) and transistor207-2 (coupled to an OR signal control line) respectively, as shown inFIG. 2A. Operation of logic selection transistors 1152 and 1154 aresimilar based on the state of the TT and FT selection signals and thedata values on the respective complementary sense lines at the time theISO signal is asserted. Logic selection transistors 1162 and 1164 alsooperate in a similar manner to control continuity of the swaptransistors 1142. That is, to OPEN (e.g., turn on) the swap transistors1142, either the TF control signal is activated (e.g., high) with datavalue on the true sense line being “1,” or the FF control signal isactivated (e.g., high) with the data value on the complement sense linebeing “1.” If either the respective control signal or the data value onthe corresponding sense line (e.g., sense line to which the gate of theparticular logic selection transistor is coupled) is not high, then theswap transistors 1142 will not be OPENed by a particular logic selectiontransistor.

The PASS* control signal is not necessarily complementary to the PASScontrol signal. For instance, it is possible for the PASS and PASS*control signals to both be activated or both be deactivated at the sametime. However, activation of both the PASS and PASS* control signals atthe same time shorts the pair of complementary sense lines together,which may be a disruptive configuration to be avoided. Logicaloperations results for the sensing circuitry illustrated in FIG. 11 aresummarized in the logic table illustrated in FIG. 12.

FIG. 12 is a logic table illustrating selectable logic operation resultsimplementable by the sensing circuitry shown in FIG. 11 in accordancewith a number of embodiments of the present disclosure. The four logicselection control signals (e.g., TF, TT, FT, and FF), in conjunctionwith a particular data value present on the complementary sense lines,can be used to select one of plural logical operations to implementinvolving the starting data values stored in the sense amplifier 1106and compute component 1131. The four control signals, in conjunctionwith a particular data value present on the complementary sense lines,controls the continuity of the pass gates 1107-1 and 1107-2 and swaptransistors 1142, which in turn affects the data value in the computecomponent 1131 and/or sense amplifier 1106 before/after firing. Thecapability to selectably control continuity of the swap transistors 1142facilitates implementing logical operations involving inverse datavalues (e.g., inverse operands and/or inverse result), among others.

The logic table illustrated in FIG. 12 shows the starting data valuestored in the compute component 1131 shown in column A at 1244, and thestarting data value stored in the sense amplifier 1106 shown in column Bat 1245. The other 3 top column headings (NOT OPEN, OPEN TRUE, and OPENINVERT) in the logic table of FIG. 12 refer to the continuity of thepass gates 1107-1 and 1107-2, and the swap transistors 1142, which canrespectively be controlled to be OPEN or CLOSED depending on the stateof the four logic selection control signals (e.g., TF, TT, FT, and FF),in conjunction with a particular data value present on the pair ofcomplementary sense lines 1105-1 and 1105-2 when the ISO control signalis asserted. The “Not Open” column corresponds to the pass gates 1107-1and 1107-2 and the swap transistors 1142 both being in a non-conductingcondition, the “Open True” corresponds to the pass gates 1107-1 and1107-2 being in a conducting condition, and the “Open Invert”corresponds to the swap transistors 1142 being in a conductingcondition. The configuration corresponding to the pass gates 1107-1 and1107-2 and the swap transistors 1142 both being in a conductingcondition is not reflected in the logic table of FIG. 12 since thisresults in the sense lines being shorted together.

Via selective control of the continuity of the pass gates 1107-1 and1107-2 and the swap transistors 1142, each of the three columns of thefirst set of two rows of the upper portion of the logic table of FIG. 12can be combined with each of the three columns of the second set of tworows below the first set to provide 3×3=9 different result combinations,corresponding to nine different logical operations, as indicated by thevarious connecting paths shown at 1275. The nine different selectablelogical operations that can be implemented by the sensing circuitry 1150are summarized in the logic table illustrated in FIG. 12.

The columns of the lower portion of the logic table illustrated in FIG.12 show a heading 1280 that includes the state of logic selectioncontrol signals. For example, the state of a first logic selectioncontrol signal is provided in row 1276, the state of a second logicselection control signal is provided in row 1277, the state of a thirdlogic selection control signal is provided in row 1278, and the state ofa fourth logic selection control signal is provided in row 1279. Theparticular logical operation corresponding to the results is summarizedin row 1247.

As such, the sensing circuitry shown in FIG. 11 can be used to performvarious logical operations as shown in FIG. 12. For example, the sensingcircuitry 1150 can be operated to perform various logical operations(e.g., AND and OR logical operations) in association with comparing datapatterns in memory in accordance with a number of embodiments of thepresent disclosure.

The present disclosure includes apparatuses and methods related toperforming comparison operations in memory. An example apparatus mightinclude a first group of memory cells coupled to a first access line. Afirst element can be stored in the first group of memory cells. Anexample apparatus might include a second group of memory cells coupledto a second access line. A second element can be stored in the secondgroup of memory cells. An example apparatus might also include sensingcircuitry configured to compare the first element with the secondelement by performing a number of AND operations, OR operations, SHIFToperations, and INVERT operations without transferring data via aninput/output (I/O) line.

Although specific embodiments have been illustrated and describedherein, those of ordinary skill in the art will appreciate that anarrangement calculated to achieve the same results can be substitutedfor the specific embodiments shown. This disclosure is intended to coveradaptations or variations of one or more embodiments of the presentdisclosure. It is to be understood that the above description has beenmade in an illustrative fashion, and not a restrictive one. Combinationof the above embodiments, and other embodiments not specificallydescribed herein will be apparent to those of skill in the art uponreviewing the above description. The scope of the one or moreembodiments of the present disclosure includes other applications inwhich the above structures and methods are used. Therefore, the scope ofone or more embodiments of the present disclosure should be determinedwith reference to the appended claims, along with the full range ofequivalents to which such claims are entitled.

In the foregoing Detailed Description, some features are groupedtogether in a single embodiment for the purpose of streamlining thedisclosure. This method of disclosure is not to be interpreted asreflecting an intention that the disclosed embodiments of the presentdisclosure have to use more features than are expressly recited in eachclaim. Rather, as the following claims reflect, inventive subject matterlies in less than all features of a single disclosed embodiment. Thus,the following claims are hereby incorporated into the DetailedDescription, with each claim standing on its own as a separateembodiment.

What is claimed is:
 1. An apparatus comprising: a first group of memorycells coupled to a first access line and configured to store a firstelement; a second group of memory cells coupled to a second access lineand configured to store a second element; sensing circuitry coupled tothe first group of memory cells and the second group of memory cells;and a controller coupled to the sensing circuitry and configured to usethe sensing circuitry to compare the first element with the secondelement by performing a number of AND operations, OR operations, SHIFToperations, and INVERT operations without transferring data via aninput/output (I/O) line.
 2. The apparatus of claim 1, wherein performingthe number of AND operations, OR operations, INVERT operations, andSHIFT operations comprises performing the number of AND operations, ORoperations, INVERT operations, and SHIFT operations without performing asense line address access.
 3. The apparatus of claim 2, furthercomprising performing the number of AND operations, OR operations,INVERT operations, and SHIFT operations using sensing circuitry on pitchwith a number of columns of complementary sense lines corresponding tothe first and second groups of memory cells.
 4. The apparatus of claim3, wherein the sensing circuitry comprises a sense amplifier and acompute component corresponding to each respective one of the number ofcolumns.
 5. The apparatus of claim 4, wherein the sense amplifierfurther comprises a primary latch and the compute component comprises asecondary latch.
 6. A method for comparing elements comprising:performing, without transferring data via an input/output (I/O) line, acomparison operation on: a first element stored in a first group ofmemory cells coupled to a first access line and to a number of senselines of a memory array; and a second element stored in a second groupof memory cells coupled to a second access line and to the number ofsense lines of the memory array; and wherein the comparison operationprovides a result that indicates whether the first element is equal tothe second element or which of the first element and the second elementis greater.
 7. The method of claim 6, further comprising storing thefirst element as a first bit-vector in the first group of memory cells,wherein each memory cell in the first group of memory cells stores arespective bit from the first bit-vector.
 8. The method of claim 7,further comprising storing the second element as a second bit-vector inthe second group of memory cells, wherein each memory cell in the secondgroup of memory cells stores a respective bit from the secondbit-vector.
 9. The method of claim 6, wherein the first element is afirst value and the second element is a second value, and wherein theresult of the comparison operation indicates whether the first value isequal to the second value or which of the first value and the secondvalue is greater.
 10. An apparatus comprising: a first group of memorycells coupled to a first access line and to a number of sense lines andconfigured to store a first element; a second group of memory cellscoupled to a second access line and to the number of sense lines andconfigured to store a second element; a third group of memory cellsconfigured to store a result of a comparison operation performed on thefirst element and the second element, the third group of cellscomprising: a number of cells coupled to a third access line and to thenumber of sense lines; and a number of cells coupled to a fourth accessline and to the number of sense lines; sensing circuitry coupled to thefirst group of memory cells, the second group of memory cells, and thethird group of memory cells; and a controller coupled to the sensingcircuitry and configured to: use the sensing circuitry to perform thecomparison operation; and cause the result of the comparison operationto be stored in the third group of memory cells without transferringdata via an input/output (I/O) line.
 11. The apparatus of claim 10,wherein the controller is further configured to cause the result of thecomparison operation to be stored as: a first bit-vector that identifiesdifferences in the first element as compared to the second element; anda second bit-vector that identifies differences in the second element ascompared to the first element.
 12. The apparatus of claim 11, whereinthe controller is further configured to use the sensing circuitry todetermine a first index that identifies a most significant one (1) bitin the first bit-vector.
 13. The apparatus of claim 12, wherein thecontroller is further configured to use the sensing circuitry todetermine a second index that identifies a most significant one (1) bitin the second bit-vector.
 14. The apparatus of claim 13, wherein thecontroller is further configured to cause, responsive to a determinationthat the first index is greater than the second index: a particularbit-vector to be stored in the number of memory cells coupled to thethird access line; and a different particular bit-vector to be stored inthe number of memory cells coupled to the fourth access line to indicatethat the first element is greater than the second element.
 15. Theapparatus of claim 14, wherein the controller is further configured tocause, responsive to a determination that the second index is greaterthan the first index: the different particular bit-vector to be storedin the number of memory cells coupled to the third access line; and theparticular bit-vector to be stored in the number of memory cells coupledto the fourth access line to indicate that the second element is greaterthan the first element.
 16. The apparatus of claim 14, wherein thecontroller is further configured to cause, responsive to a determinationthat the first and second indices are the same: the particularbit-vector to be stored in the number of memory cells coupled to thethird access line; and the particular bit-vector to be stored in thenumber of memory cells coupled to the fourth access line to indicatethat the first element is equal to the second element.
 17. A method forcomparing elements comprising: performing, without transferring data viaan input/output (I/O) line, a comparison operation in memory on: aplurality (M) of first elements stored in a first group of memory cellscoupled to a first access line and to a number (C) of sense lines of amemory array; and a plurality (M) of second elements stored in thesecond group of memory cells coupled to a second access line and to theC sense lines of the memory array; and providing a comparison operationresult that indicates whether the M first elements are equal to the Msecond elements or which of the M first elements and the M secondelements are greater.
 18. The method of claim 17, wherein each of the Mfirst elements and the M second elements are comprised of N bits. 19.The method of claim 18, wherein M is equal to C divided by N.
 20. Themethod of claim 18, wherein each of the N bits in each of the M firstelements and the M second elements are associated with an index andwherein bits from corresponding elements that are associated with a sameindex are stored in memory cells that are coupled to a same sense linefrom the C sense lines.
 21. The method of claim 18, further comprising,identifying a most significant bit (MSB) for the M first elements andthe M second elements.
 22. The method of claim 21, further comprising,identifying a least significant bit (LSB) for each of the M firstelements and the M second elements.
 23. The method of claim 22, whereinperforming the comparison operation further comprises performing anumber of iterations of operations using a mask element to isolatecorresponding elements from the M first elements and the M secondelements, wherein the mask element is created using the MSB for the Mfirst elements and the M second elements.
 24. The method of claim 23,wherein each iteration of operations of the number of iterations ofoperations further comprises determining whether an element from the Mfirst elements is greater than a corresponding element from the M secondelements.
 25. The method of claim 24, wherein each iteration ofoperations of the number of iterations of operations further comprisesdetermining whether an element from the M first elements is less thanthe corresponding element from the M second elements.
 26. The method ofclaim 25, wherein each iteration of operations of the number ofiterations of operations further comprises determining whether anelement from the M first elements is equal to the corresponding elementfrom the M second elements.
 27. The method of claim 25, wherein eachiteration of operations of the number of iterations of operationsfurther comprises performing an AND operation on corresponding elementsfrom the M first elements and the M second elements to find shared bits,and wherein a shared bit refers to a particular bit in an element fromthe M first elements and having a particular index being the same as acorresponding bit in an element from the M second elements and havingthe particular index.
 28. The method of claim 27, wherein each iterationof operations of the number of iterations of operations furthercomprises performing an INVERT operation using a result of the ANDoperation to identify bits that are not shared between correspondingelements.
 29. The method of claim 28, wherein each iteration ofoperations of the number of iterations of operations further comprises:identifying differences in the second element as compared to the firstelement by performing an AND operation on a result of the INVERToperation and a first element from the corresponding elements;identifying differences in the first element as compared to the secondelement by performing an AND operation on the result of the INVERToperation and the second element from the corresponding elements;identifying a first most significant one (1) bit from a result of theAND operation using the result of the INVERT operation and a firstelement from the corresponding elements; and identifying a second mostsignificant one (1) bit from the result of the AND operation using theresult of the INVERT operation and a second element from thecorresponding elements; wherein identifying the first most significantone (1) bit and the second most significant one (1) bit includesperforming a plurality of AND operations, a plurality of BLOCKORoperations, and a plurality of SHIFT operations; and wherein the firstmost significant one (1) bit and the second most significant one (1) bitare identified using the LSB.
 30. The method of claim 29, wherein eachiteration of operations of the number of iterations of the operationsfurther comprises: storing results of the comparison operation in athird group of memory cells coupled to a third access line and to thenumber of sense lines of the memory array; wherein the result of thecomparison operation is based on a comparison between the first mostsignificant one (1) bit and the second most significant one (1) bit; andwherein the results of the comparison operation is updated during eachiteration of operations of the number of iterations of operations usingan OR operation.